@article{kulesza_burns_woodley_gatiboni_shupe_hicks_2022, title={Distribution and Fractionation of Zinc and Copper in Poultry Litters Across North Carolina}, volume={5}, ISSN={["1532-2416"]}, DOI={10.1080/00103624.2022.2072866}, abstractNote={ABSTRACT Zinc (Zn) and copper (Cu) are necessary micronutrients for crop production. However, excess Zn and Cu applied through land application of manures can result in Zn and Cu toxicity, reducing yields. With many integrators and little information on the formulation of poultry feeds in North Carolina (NC), it is difficult to predict the fractionation of Zn and Cu in litters generated at facilities, as the form of Zn and Cu determines mobility and bioavailability. Therefore, statewide data from the NC Department of Agriculture and Consumer Services was analyzed to determine regional variation of total Zn and Cu. The results showed a significant effect of the region on the total Zn and Cu among the three production regions in the state. Additionally, 11 broilers and broiler breeder litter samples were analyzed to determine the distribution of Zn and Cu in acid soluble, reducible, oxidizable, and residual fractions. Total Zn and Cu averaged 675 mg/kg and 629 mg/kg, respectively. There was a significant interaction between the region and Zn concentration in the fractions. However, there was no region interaction when converted to a percentage of the sum of the fractions, indicating Zn partitions similarly across a wide range of concentrations and 37%, 40%, 21%, and 0.6% was found in the acid soluble, reducible, oxidizable, and residual fractions, respectively. Region did not have an effect on Cu fractionation, with 26%, 8%, 67%, and 2% of Cu in the acid-soluble, reducible, oxidizable, and residual fractions, respectively. Results indicate greater bioavailability and mobility potential for Zn as compared to Cu.}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Kulesza, Stephanie and Burns, Joseph and Woodley, Alex and Gatiboni, Luciano and Shupe, Maggie and Hicks, Kristin}, year={2022}, month={May} }
 @article{burns_kulesza_vann_woodley_2022, title={Effects of Nitrogen Source and Rate on Soybean Yield and Quality}, volume={9}, ISSN={["1532-2416"]}, url={https://doi.org/10.1080/00103624.2022.2118299}, DOI={10.1080/00103624.2022.2118299}, abstractNote={ABSTRACT The poultry industry in North Carolina (NC) has increased substantially over the past few decades, which has led to widespread availability of poultry litter. While many grain producers in NC utilize litter in their fertilization programs, it is typically applied to the corn or wheat crops that are in the rotation with soybean, instead of directly prior to soybeans. However, there is interest in application to soybean. Therefore, three field sites were established across NC in both 2019 and 2020, with four replicates of 11 treatments: four litter rates (22.4, 44.8, 89.7 and 134.5 Mg/hectare), six inorganic nitrogen (N) fertilizer rates (16.8, 33.6, 67.3, 134.5, 201.8, and 269.0 kg N/hectare), and a control. The impact of these treatments on biomass production, tissue N, plant population, yield, and grain quality were investigated. There was no significant effect on yield in 2019; however, there was a significant effect on yield in 2020, showing a negative correlation with inorganic N fertilizer in Plymouth and a 22% reduction in yield over the range of inorganic N treatments. It is possible there was an increased salt effect in these plots, as there was a negative response in plant population at five of six site years. While there was a positive correlation between grain protein and increasing inorganic N rate, growers are not paid based on grain quality. The results of this study suggest N application at planting is not beneficial for growers, but litter could be applied to meet soybean phosphorus or potassium demands.}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Burns, Joseph and Kulesza, Stephanie and Vann, Rachel and Woodley, Alex}, year={2022}, month={Sep} }
 @article{riar_spears_burns_jordan_zhang_rufty_2014, title={Persistence of Benghal dayflower (Commelina benghalensis) in sustainable agronomic systems: Potential impacts of hay bale storage, animal digestion, and cultivation}, volume={38}, DOI={10.1080/21683565.2013.839486}, abstractNote={Experiments were conducted to evaluate factors affecting persistence of the invasive, federal noxious weed Benghal dayflower in sustainable agronomic systems. Seeds were exposed to a range of temperatures simulating those found in hay bales in the field and periodically tested for viability over 21 days. Seeds were nonviable after one day at 65 °C and after 14 days at 50 or 45 °C. A second series of experiments examined the effects of simulated rumen digestion on germination and viability of Benghal dayflower seeds and the response was compared to that with seeds of five other common weed species. Time courses revealed that seeds from the other weeds were acutely damaged by digestion and viability depressed after 48 and 96 h, but germination of Benghal dayflower seeds was increased at 48 h, and only a slight decrease occurred after 96 h. In the third experimental series, stem fragments of Benghal dayflower were buried in soil at 2 and 6 cm depths and exposed to aerial temperatures of 20, 25, 30, and 35 °C for 30 days. Root development occurred at both depths, but leaf development was restricted at 6 cm and subterranean spathe development was not found at 2 cm. Temperatures higher than 25 °C favor regeneration at both depths. The results, collectively, show the difficulty encountered when trying to control or eradicate Benghal dayflower in sustainable farming systems. Farms must avoid using fresh hay as animal feed when Benghal dayflower is present in hay fields, as little restraint on seed viability will be exerted during digestion and generation of manure. Cultivation is unlikely to be an effective control strategy during summer months when Benghal dayflower is growing most aggressively, because soil temperatures are optimal for vegetative regeneration.}, number={3}, journal={Agroecology and Sustainable Food Systems}, author={Riar, M. K. and Spears, J. F. and Burns, J. C. and Jordan, D. L. and Zhang, C. X. and Rufty, T. W.}, year={2014}, pages={283–298} }
 @article{burns_fisher_2013, title={Steer Intake, Digestion, and Ingestive Behavior of Switchgrass and Alfalfa Hays}, volume={53}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2012.07.0458}, abstractNote={ABSTRACT Perennial, warm‐season grasses cut for hay frequently have inadequate crude protein (CP) concentrations for acceptable ruminant performance. This study determined the influence of alfalfa ( Medicago sativa L.) as a CP supplement to steers ( Bos taurus ) fed switchgrass ( Panicum virgatum L.) hay harvested at the early‐heading stage. Diets of 100% switchgrass (SG) and 100% alfalfa (AL) were included along with 25, 50, and 75% mixtures of the hays making five treatments. Steer dry matter intake (DMI), whole tract dry matter digestibility (DMD), eating behavior, and masticate characteristics were estimated. Steer DMI averaged 1.35 kg 100 kg −1 body weight (BW) for 100% SG and increased linearly ( P < 0.01) to 2.93 kg 100 kg −1 BW for 100% AL. Also, DMD increased linearly ( P < 0.01) from 484 g kg −1 for 100% SG to 653 g kg −1 for 100% AL. Concentration of CP was 51 g kg −1 for SG and increased quadratically ( P < 0.01) to 241 g kg −1 with increasing AL while neutral detergent fiber (NDF) decreased quadratically ( P < 0.01) from 792 g kg −1 for SG to 407 g kg −1 for AL. Masticate in vitro dry matter disappearance (IVDMD) increased quadratically ( P < 0.01) from 509 g kg −1 for SG to 660 g kg −1 in AL whereas CP increased linearly ( P < 0.01) from 60 g kg −1 for SG to 230 g kg −1 in AL. Increasing AL of the as‐fed hay linearly decreased ( P < 0.01) chews per gram of dry matter, IVDMD, and CP but increased quadratically ( P < 0.01) chews per gram of NDF. Steers readily ate the SG:AL combinations; AL could thus provide a source of CP for SG based diets.}, number={2}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S.}, year={2013}, month={Mar}, pages={716–723} }
 @article{burns_fisher_2013, title={Steer Performance and Pasture Productivity among Five Perennial Warm-Season Grasses}, volume={105}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2012.0142}, abstractNote={Grazing systems in the mid‐Atlantic region of the United States typically utilize perennial warm‐season grasses. Bermudagrass [ Cynodon dactylon (L.) Pers.] has served this function in the region, but the resulting animal performance has been modest. Steer and pasture performance of three native grasses, big bluestem (BBS) ( Andropogon gerardii Vitman), eastern gamagrass (GG) ( Tripsacum dactyloides L.), and switchgrass (SG) ( Panicum virgatum L.), and an introduced Old World bluestem, Caucasian bluestem (CBS) [ Bothriochloa bladhii (Retz.) S.T. Blake], were compared during 6 yr with Tifton 44 bermudagrass (BG) as the control. During summer (June–September), steers continuously stocked on the alternative grasses gained similarly (0.73 kg d −1 ) but more rapidly than those grazing BG (0.49 kg d −1 ). Stocking of BG at 9.9 steers ha −1 was greater than the alternative grasses (5.7 steers ha −1 ), which were similar. Although animal days per hectare were greater for BG, weight gain per hectare was similar (mean = 357 kg ha −1 ) because of the differential gain per day. Canopies of BG and CBS had the least proportion of their mass in leaf (24.5 and 25.0%, respectively) compared with GG (58.2%), BBS (35.6%), and SG (30.9%), with the latter two similar. In general, any one of the grasses can serve as the warm‐season component; however, pastures of BBS, GG, SG, and CBS would be more appropriate for growing ruminants, although at a reduced stocking rate, than BG. The latter would provide adequate forage for mature animals.}, number={1}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Fisher, D. S.}, year={2013}, pages={113–123} }
 @article{alvarez almora_huntington_burns_2012, title={Effects of supplemental urea sources and feeding frequency on ruminal fermentation, fiber digestion, and nitrogen balance in beef steers}, volume={171}, ISSN={["1873-2216"]}, DOI={10.1016/j.anifeedsci.2011.10.012}, abstractNote={The objective of two experiments was to evaluate non-protein N supplementation with protected urea sources in terms of rumen fermentation products, nutrient digestibility, and N balance in ruminally fistulated beef steers (initial bodyweight 239 ± 18 kg) fed switchgrass hay. Experiment 1 compared urea with Optigen II®, and Experiment 2 compared urea with RumaPro®. In both experiments, supplements (400 g/kg of daily dietary dry matter) were fed once daily or every 2 h in a balanced design. Supplements contained soybean hulls, corn grain, vitamins, and minerals as well as non-protein N sources. Non-protein N provided 0.18 g/g of dietary N. Switchgrass hay was fed once daily, at the same time as the supplement in the once-daily treatments. Dry matter intake (4.1 kg/d in Experiment 1, 4.5 kg/d in Experiment 2), dry matter digestibility (P<0.25, 0.58 ± 0.014 g/g in Experiment 1, 0.58 ± 0.010 g/g in Experiment 2), N balance (P<0.83, 11.3 ± 1.9 g/d in Experiment 1, 11.8 ± 3.6 g/d in Experiment 2), ruminal ammonia concentrations (P<0.29, 15.2 ± 1.4 mM in Experiment 1, 11.8 ± 0.6 mM in Experiment 2), and ruminal short-chain fatty acid concentrations (P<0.13, 77.7 ± 3.0 mM in Experiment 1, 75.4 ± 3.0 mM in Experiment 2) were not affected by feeding protected urea sources. Providing a steady supply of ruminally degradable N by feeding supplement every 2 h vs once daily decreased ruminal ammonia concentrations by approximately one-half by 4 h after feeding hay (P<0.01 in both experiments) and increased (P<0.02 in Experiment 1, P<0.08) in Experiment 2) apparent digestibility of dry matter (0.58–0.62 in Experiment 1, 0.56–0.61 in Experiment 2) and dietary fiber components.}, number={2-4}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Alvarez Almora, E. G. and Huntington, G. B. and Burns, J. C.}, year={2012}, month={Feb}, pages={136–145} }
 @article{burns_fisher_2012, title={Grazing Management of Flaccidgrass Pastures in Autumn}, volume={52}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2012.01.0021}, abstractNote={ABSTRACT ‘Carostan’ flaccidgrass ( Pennisetum flaccidum Griseb.) is a perennial warm‐season grass with potential for pasture, but appropriate autumn (September to November) management is needed to maintain forage mass (FM) production and prevent declines in plant density. We evaluated 10 treatments over 3 yr consisting of an ungrazed control, four treatments with multiple grazing events (MG), four treatments with a single grazing event (SG), and one treatment grazed after frost. The winter residues after the treatments were greatest ( P < 0.01) when ungrazed compared with the grazed treatments (3347 vs. 2265 kg ha −1 ) and differed ( P ≤ 0.01) among and between ( P < 0.01) the MG and SG treatments. Plant density decreased from 13 to 27% with 8 to 10 wk of regrowth before frost. Greater plant density decline (60%) occurred when plots were grazed three times and only allowed 4 wk of regrowth before frost. Total nonstructural carbohydrates (TNC) of ungrazed basal stems, crowns, and roots sampled in December were 158, 193, and 250 g kg −1 , respectively, and when grazed were 124, 183, and 253 g kg −1 , respectively. By April TNC had declined 56, 35, and 25%, respectively. Plant density was not related to autumn total FM, FM regrowth, or overwintering residue but was related ( P ≤ 0.02) to TNC of December roots ( r = 0.59) and TNC of April basal stems ( r = 0.42), crowns ( r = 0.61), and roots ( r = 0.66). Allowing 6 wk of regrowth before frost minimized plant density losses for flaccidgrass.}, number={5}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S.}, year={2012}, month={Sep}, pages={2392–2402} }
 @article{burns_fisher_pond_2012, title={Steer Performance, Intake, Digesta Kinetics, and Pasture Productivity of Flaccidgrass at Each of Three Forage Masses}, volume={104}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2011.0256}, abstractNote={‘Carostan’ flaccidgrass ( Pennisetum flaccidum Griseb.) is a perennial, warm‐season grass with potential in forage systems for the mid‐Atlantic region. Using established flaccidgrass pastures, we estimated steer ( Bos taurus ) average daily gain (ADG), stocking rate, and pasture productivity in a 4‐yr experiment. Pastures were continuously and variably stocked at a forage mass (FM) of 1895 (Short), 4186 (Medium), and 5297 (Tall) kg ha −1 (linear; P < 0.01). Steer ADG was similar among FM (mean = 0.65 kg d −1 ). The Short was stocked at 8.3 steers ha −1 and numbers decreased linearly ( P < 0.01) to 7.2 steers ha −1 for Tall. Animal days ha −1 decreased linearly ( P < 0.01) from 963 (Short) to 756 (Tall). Weight gain ha −1 did not vary significantly ( P = 0.14). Effective feed units (kg ha −1 ) declined linearly ( P = 0.02) from 3756 for the Short to 2842 for Tall. Analysis of digesta kinetics revealed no differences among FM in rate of passage, retention time of liquid or solid phases, fill, or fecal output. Diets selected by steers among FM were similar in concentration of in vitro dry matter disappearance (mean = 690 g kg −1 ); however, CP declined linearly ( P = 0.03) while NDF increased ( P = 0.01) with increasing FM. Steer ADG was greater ( P = 0.03) in Period 1 (0.77 kg d −1 up to early July) compared with Period 2 (0.53 kg d −1 after early July) and attributed to greater forage quality in Period 1. Flaccidgrass is a productive, perennial forage that can provide quality pasture during the summer.}, number={1}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Fisher, D. S. and Pond, K. R.}, year={2012}, pages={26–35} }
 @article{burns_2011, title={Advancement in Assessment and the Reassessment of the Nutritive Value of Forages}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.06.0334}, abstractNote={ABSTRACTForages, primary producers of carbon compounds, provide energy and nutrients when consumed by herbivores, resulting in “value‐added” animal products as meat, milk, and fiber and, in some cases, recreation. How a forage supports value‐added products of interest has been a concern since the mid 1800s. The characteristic of a forage that composes its nutritive value (NVAL) and its consumption and conversion by the animal determines the quality of the nutrient entity and provides an estimate of its forage quality. The first system to address forage NVAL emerged in the mid 1880s and was termed the Weende proximate analysis. Forages were separated into crude protein (CP), crude fiber (CF), ether extract (EE), nitrogen‐free extract (NFE), ash, and water. The concept of nutrient entity followed in the 1950s. By the mid 1960s, the neutral detergent fiber (NDF) system partially replaced proximate analysis and the two, along with innovations in solubility, serve as methodologies for estimating NVAL. An assessment of NVAL from the microbial view point was introduced in the early 1960s by the two‐stage in vitro dry matter disappearance (IVDMD) method, followed in the 1970s by continuous cultures. Innovation in spectral technology introduced near infrared spectrophotometry in the mid 1980s providing a rapid analysis of the NVAL fractions. A reassessment of the approach to estimating forage quality, based on the microflora's view of “particle value,” using near infrared spectral scans of the “as fed” forage has been proposed.}, number={2}, journal={CROP SCIENCE}, author={Burns, J. C.}, year={2011}, month={Mar}, pages={390–402} }
 @article{xu_chen_cheng_sharma-shivappa_burns_2011, title={Delignification of switchgrass cultivars for bioethanol production}, volume={6}, number={1}, journal={BioResources}, author={Xu, J. L. and Chen, Y. and Cheng, J. J. and Sharma-Shivappa, R. R. and Burns, J. C.}, year={2011}, pages={707–720} }
 @article{burns_fisher_pond_2011, title={Flaccidgrass Forage Mass and Canopy Characteristics Related to Steer Digesta Kinetics and Intake}, volume={51}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2011.05.0284}, abstractNote={ABSTRACT ‘Carostan’ flaccidgrass ( Pennisetum flaccidum Griseb.) has potential as a perennial, warm‐season grass for pastures. This 2‐yr study examined digesta kinetics, dry matter intake (DMI), and diet of steers as related to canopy characteristics. Steers ( Bos taurus L.) were continuously and variably stocked at canopy heights of Short (15 to 20 cm), Medium (30 to 40 cm), and Tall (45 to 55 cm) with forage mass (FM) of 1245, 2600, and 3585 kg ha −1 , respectively (linear; p < 0.01). Neither mean retention time nor passage rate of either liquid or digesta phases were altered by FM. Fecal output increased linearly ( p = 0.04) from Short to Tall (0.643 to 0.739 kg 100 −1 kg body weight [BW]) indicating a possible variation in DMI. However, DMI and digestible DMI (based on leaf in vitro dry matter disappearance [IVDMD]) were similar among FM (mean = 1.99 and 1.29 kg 100 −1 kg BW). Leaf composed 24.3% of the three canopies and was not altered by FM. Stem increased linearly ( p = 0.01) from 40.1 to 53.1% with height whereas dead tissue declined linearly ( p = 0.06) from 34.8 to 23.4%. Steers selected diets (1 yr data), regardless of FM, similar in IVDMD (mean = 713 g kg −1 ) and neutral detergent fiber (NDF) (mean = 486 g kg −1 ). In general, steer digesta kinetics were not influenced by FM as animals adjusted grazing behavior to result in similar responses. Flaccidgrass canopies were flexible and no particular optimum FM was detecting for an optimum diet. The influence of FM on pasture productivity (regrowth after defoliation) requires additional study.}, number={6}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S. and Pond, K. R.}, year={2011}, month={Nov}, pages={2895–2903} }
 @article{burns_2011, title={Intake and Digestibility among Caucasian Bluestem, Big Bluestem, and Switchgrass Compared with Bermudagrass}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2011.01.0050}, abstractNote={Warm‐season perennial grasses, mainly bermudagrass [ Cynodon dactylon (L.) Pers.], have been a major source of hay for ruminant systems across the upper southern United States. This study compares the quality of Caucasian bluestem [ Bothriochloa caucasica (Trin.) C.E. Hubbard ‘Caucasian’] (CBS) with ‘Kanlow’ switchgrass ( Panicum virgatum L.) (SG), and big bluestem ( Andropogon gerardi Vitman) (BBS), relative to ‘Coastal’ and ‘Tifton 44’ bermudagrasses, as forages for the upper south. Four intake and digestion experiments, with associated diet characteristics, were conducted using steers. In experiment (Exp.) 1, CBS regrowth (45 d) compared with initial growth had greater ( P = 0.01) daily dry matter (DM) intake (DMI) [2.33 vs. 1.91 kg 100 −1 kg body weight (BW)] and apparent DM digestibility (DMD) (664 vs. 617 g kg −1 ). Initial growth bermudagrass had greater ( P < 0.01) DMI than CBS (2.61 vs. 1.91 kg 100 kg −1 BW) and similar DMD (mean = 619 g kg −1 ). In Exp. 2, initial and regrowth (45 d) CBS, compared with SG, had greater ( P < 0.01) DMI (2.06 vs. 1.23 kg 100 −1 kg BW). In Exp. 3, regrowth CBS and BBS had similar DMI (mean = 1.83 kg 100 −1 kg BW) and DMD (mean = 637 g kg −1 ). In Exp. 4, initial and regrowth (53 d) CBS and regrowth (57 d) BBS had similar DMI (mean = 2.29 kg 100 −1 kg BW), but CBS had greater ( P = 0.01) DMD (602 vs. 566 g kg −1 ). The DMI and DMD of all hays in all experiments ( n = 15) were correlated ( r = 0.66, P < 0.01). In general all hays can contribute to ruminant production systems.}, number={5}, journal={CROP SCIENCE}, author={Burns, J. C.}, year={2011}, month={Sep}, pages={2262–2275} }
 @article{burns_2011, title={Maturity and Regrowth Influences on Quality of Caucasian Bluestem Hay}, volume={51}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2010.10.0570}, abstractNote={Caucasian bluestem [CBS; Bothriochloa caucasica (Trin.) C.E. Hubbard 'Caucasian'] appears adapted to the mid-Atlantic region. Three experiments, one with sheep and two with steers, were conducted to assess hay quality. In Experiment (Exp.) 1, initial growth was cut at early boot, anthesis, and postanthesis and regrowth cut at early boot and anthesis (five treatments) and evaluated by wether sheep. All treatments, except regrowth anthesis were also evaluated in a preliminary experiment with steers. In Exp. 2, regrowth was cut at the same three initial growth stages as in Exp. 1 and evaluated by steers. Sheep readily ate CBS hay, consuming 1.88 kg 100 kg ―1 body weight (BW) when the hay was cut at early boot, with apparent dry matter digestion (DMD) of 647 g kg ―1 . Intake decreased linearly by postanthesis to 1.45 kg 100 kg ―1 BW with DMD of 548 g kg ―1 . Steers also readily ate early-boot CBS hay, averaging 2.49 kg 100 kg ―1 BW with DMD of 661 g kg ―1 . Intake decreased linearly by postanthesis to 1.48 kg 100 kg ―1 BW with a DMD of 589 g kg ―1 . Sheep and steer intake was well correlated (r = 0.951; P = 0.05) as was DMD (r = 0.939; P = 0.06). In Exp. 2, steers readily consumed regrowth hay, averaging 2.73 kg 100 kg ―1 BW for the early-boot cut with a DMD of 670 g kg ―1 . Intake declined linearly by postanthesis to 1.57 kg 100 kg ―1 BW with a DMD of 517 g kg ―1 . Hays of CBS can provide desirable quality for animal production systems if it is cut by the early-boot stage in the mid-Atlantic region of the United States.}, number={4}, journal={CROP SCIENCE}, author={Burns, J. C.}, year={2011}, month={Jul}, pages={1840–1849} }
 @article{burns_fisher_pond_2011, title={Steer performance, intake, and digesta kinetics of switchgrass at three forage masses}, volume={103}, DOI={10.2134/agronj2010.0357}, abstractNote={Management strategies to accommodate switchgrass (Panicum virgatum L.) in production systems have been reported but impact of variation in forage mass (FM) on animal responses and pasture stands are lacking. This 4‐yr study assessed canopy and stand characteristic and steer (Bos taurus) responses when ‘Kanlow’ switchgrass was continuously and variably stocked to produce Short (S) (10–16 cm), Medium (M) (20–26 cm), and Tall (T) (35–41 cm) canopy heights. From April to mid‐July (Period 1) FM for S, M, and T average 818, 2164, and 3294 kg ha−1, respectively. Canopies had similar in vitro organic matter disappearance (IVOMD) (626 g kg−1), but increased in neutral detergent fiber (NDF) from S (645 g kg−1) to T (665 g kg−1). Diets decreased in IVOMD from S (744 g kg−1) to T (706 g kg−1). Digesta kinetics data were not altered and average daily gain was similar among FM (1.11 kg d−1). From mid‐July to late September (Period 2), FM averaged 465, 1282, and 2388 kg ha−1, respectively, for S, M, and T. Whole canopy IVOMD increased from S (484 g kg−1) to T (538 g kg−1), whereas NDF was not altered (696 g kg−1). Steers selected a diet similar in IVOMD (685 g kg−1) and NDF (667 g kg−1) among FM. Estimates of dry matter intake (kg 100−1 kg body weight) increased from S (1.75) to T (2.54). Tiller density decreased from T to S. Continuously stocked switchgrass at 20 to 40 cm remained vegetative with 1279 tillers m−2 after 3 yr of grazing.}, number={2}, journal={Agronomy Journal}, author={Burns, J. C. and Fisher, D. S. and Pond, K. R.}, year={2011}, pages={337–350} }
 @article{burns_fisher_2011, title={Stocking Strategies as Related to Animal and Pasture Productivity of Endophyte-Free Tall Fescue}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2011.01.0022}, abstractNote={ABSTRACT Tall fescue ( Festuca arundinacea Schreb.) is a well adapted perennial grass used for pasture across the north–south transition zone in the United States. This 3‐yr trial evaluated three stocking strategies to utilize well‐fertilized spring (April to July) growth of endophyte‐free tall fescue for steer and pasture production. Continuous stocked (CS) was compared with a daily allowance (DA) or lax rotation (LR) (7 to 12 d). Forage mass (in kilograms per hectare) averaged 2673 for CS, 3057 at turn on and 2844 residual for DA, and 2851 at turn on and 2559 residual for the LR. Canopies were similar being mainly leaf (54.9%), followed by dead (32.6%), stem (11.9%), and head (0.5%) fractions. Steer daily gains (0.95 kg), stocking rate (6.7 steers ha −1 ), gain per hectare (585 kg), and effective feed units (3111 kg ha −1 ) were similar among stocking strategies. Canopy in vitro true organic matter disappearance (IVTOD) was similar (747 g kg −1 ) among treatments but differed in crude protein (CP), averaging 186 g kg −1 for CS vs. 198 g kg −1 for rotations. Furthermore, DA was less in CP than LR (189 vs. 207 g kg −1 ) but greater in neutral detergent fiber (NDF) (623 vs. 594 g kg −1 ). Diet selected was similar among treatments in IVTOD (885 g kg −1 ), CP (245 g kg −1 ), and NDF (457 g kg −1 ) as was daily grazing time of 11.5 h when monitored by Vibracorder or 12.3 h when monitored by computer. Well‐fertilized tall fescue pastures free of toxic endophyte can accommodate a range of stocking strategies when efficiently utilized in animal production systems.}, number={6}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S.}, year={2011}, month={Nov}, pages={2868–2877} }
 @article{burns_fisher_pond_2011, title={Tall Fescue Forage Mass and Canopy Characteristics on Steer Ingestive Behavior and Performance}, volume={51}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.10.0578}, abstractNote={Tall fescue (Festuca arundinacea Schreb.) is a well-adapted perennial pasture species utilized across the north-south transition zone of the United States. This 3-yr trial evaluated the influence of three forage masses (FM) on steer and pasture responses for spring (April to July) and fall (October) growths. Spring FM averaged 1450 kg ha ―1 (Short), 3032 kg ha ―1 (Medium), and 3812 kg ha ―1 (Tall) for the three treatments. Canopy in vitro true organic matter disappearance (ITOD) decreased linearly from Short (797 g kg ―1 ) to Tall (771 g kg ―1 ). Steer daily gains (0.88 kg) and gains per hectare (392 kg ha ―1 yr ―1 ) were not altered by FM, but the mean number of steers per hectare decreased linearly from Short (8.2 steers ha ―1 ) to Tall (6.1 steers ha ―1 ) as did effective feed units per hectare (2256 to 1712 kg ha ―1 yr ―1 ). Canopies were predominately leaf (53%) and averaged 847 g kg ―1 ITOD with estimates similar among FM treatments. Diet ITOD declined linearly from Short (870 g kg ―1 ) to Tall (839 g kg ―1 ) as did crude protein (CP) (from 235 to 192 g kg ―1 ). In the fall, FM averaged 1556, 3228, and 3494 kg ha ―1 for the three FM treatments. Canopy ITOD averaged 774 g kg ―1 and was not altered by FM. Canopy leaves averaged 60% with an ITOD of 864 g kg ―1 and were similar among FM treatments. Diets selected averaged 834 g kg ―1 ITOD and 233 g kg ―1 CP and were not altered by FM. Tall fescue pasture free of toxic endophyte needs to be effectively utilized to enhance production and can be managed flexibly in grazing systems.}, number={4}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S. and Pond, K. R.}, year={2011}, month={Jul}, pages={1850–1864} }
 @article{huntington_leonard_burns_2011, title={Technical note: Use of near-infrared reflectance spectroscopy to predict intake and digestibility in bulls and steers}, volume={89}, ISSN={["1525-3163"]}, DOI={10.2527/jas.2010-3376}, abstractNote={Multiple fecal samples were collected from growing Angus bulls (264 to 419 kg of BW, 3.0 to 11.4 kg/d of DMI) to predict DMI of a corn-silage-based diet. Contemporaneous digestion trials were conducted with the same diet in 12 steers in yr 1 to 3 and bulls in yr 4. Near-infrared spectra from fecal samples (n = 730 from 282 growing bulls, n = 240 from 36 steers and 12 bulls for digestion trials) were obtained from dried and ground fecal samples, and modified partial least squares regression was used to develop equations to predict DMI and DM digestibility (DMD). Although mean predicted DMI of the growing bulls (7.52 ± 0.04 kg/d or 22.4 ± 0.1 g/kg of BW) was within 2% of mean measured DMI (7.63 ± 0.06 kg/d or 22.7 ± 0.1 g/kg of BW), the mean of paired differences within samples (0.11 ± 0.04 kg/d or 0.3 ± 0.1 g/kg of BW) was greater (P < 0.01) than zero. Measured DMD (72.3 ± 0.5%) was identical (P < 0.97) to predicted DMD (72.3 ± 0.5%), and DMD for bulls in the digestion trial did not differ (P < 0.27) from DMD for steers. Prediction of intake requires incorporation of some measured values from the set of fecal samples to be predicted. Lack of similarity between spectra of fecal grab samples from the growing bulls and daily fecal collection of steers and bulls in the digestion trials in this study indicates the need for further verification before prediction of DMD with fecal grab samples.}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Huntington, G. B. and Leonard, E. S. and Burns, J. C.}, year={2011}, month={Apr}, pages={1163–1166} }
 @article{sanderson_burns_2010, title={Digestibility and Intake of Hays from Upland Switchgrass Cultivars}, volume={50}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2010.03.0126}, abstractNote={Switchgrass (Panicum virgatum L.) cultivars with improved forage quality would fill a forage gap during summer when hot dry weather reduces production of cool‐season forages on marginal lands of the northeastern United States. ‘Cave‐in‐Rock’, ‘Trailblazer’, ‘Shawnee’, and ‘Pathfinder’ switchgrass hays were harvested and baled from field plots at Rock Springs, PA, on 29 June 2007, 16 June 2008 (Cut 1), and 8 Aug. 2008 (Cut 2) and fed to mature wether sheep. In 2008, Trailblazer was unavailable so Pathfinder was substituted. Morphological development stage and leaf and stem proportions were determined at each harvest. In 2007, cultivars did not differ in digestion of dry matter (DM) or fiber constituents and sheep consumed switchgrass hays similarly. In 2008, sheep consumed hay of switchgrass cultivars similarly but consumed more of Cut 1 than Cut 2 hay. Cut 1 hay also had greater neutral detergent fiber (NDF) and hemicellulose digestibility than Cut 2 hay. Shawnee consistently had lower DM, fiber, and crude protein digestibility (CPD) than Pathfinder in both cuts. Switchgrass cultivars selected for improved DM disappearance in vitro did not have greater DM or fiber digestion compared with Cave‐in‐Rock when fed to sheep. Differences among cultivars in nutritive value and in vivo fiber and DM digestion mostly were due to differences in plant maturity and leaf‐to‐stem ratio.}, number={6}, journal={CROP SCIENCE}, author={Sanderson, Matt A. and Burns, J. C.}, year={2010}, pages={2641–2648} }
 @article{burns_fisher_2010, title={Eastern Gamagrass Management for Pasture in the Mid-Atlantic Region: I. Animal Performance and Pasture Productivity}, volume={102}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2009.0265}, abstractNote={Eastern gamagrass [Tripsacum dactyloides (L.) L.] (EG) is a native, warm‐season perennial grass with potential as pasture for the eastern United States, but its value has not been well studied. The objective of this 4‐yr experiment was to estimate forage mass (FM) for EG that maximizes steer (Bos taurus) performance and pasture productivity. Five treatments (three continuously and two rotationally stocked) were compared with a continuously stocked ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] control. The three continuously stocked treatments had mean FM (10‐cm stubble) levels of 559 kg ha−1 (Short), 1103 kg ha−1 (Medium), and 1932 kg ha−1 (Tall). Rotational treatments consisted of two subdivisions with steers moved on a 10 to 14 d interval (FM = 1348 kg ha−1) and10 subdivisions with steers moved every 3 to 4 d with a 27 to 36 d regrowth interval (FM = 2061 kg ha−1). The average daily gain (ADG) from the Medium continuously stocked treatment was greatest at 0.90 kg (P = 0.02) and produced similar annual gain per hectare (735 vs. 749 kg ha−1; P = 0.08) as Short. Rotational pastures had greater FM than continuously stocked (1705 vs. 1198 kg ha−1; P = 0.03), but the least ADG (0.67 vs. 0.79 kg; P = < 0.01). Bermudagrass produced less ADG than EG (0.57 vs. 0.79 kg; P < 0.01), but gain per hectare was similar (662 kg ha−1) and stocking rate was greater (10.0 vs. 6.7 head ha−1; P < 0.01). Eastern gamagrass has potential as a special purpose pasture for the region when greater ADG is the goal.}, number={1}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Fisher, D. S.}, year={2010}, pages={171–178} }
 @article{burns_fisher_2010, title={Eastern Gamagrass Management for Pasture in the Mid-Atlantic Region: II. Diet and Canopy Characteristics, and Stand Persistence}, volume={102}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2009.0339}, abstractNote={Eastern gamagrass [Tripsacum dactyloides (L.) L.] (EG), a native warm‐season perennial grass, lacks evaluation for use in grazing systems. Our objective was to test EG in a 4‐yr experiment to estimate forage mass (FM) that maximizes steer (Bos taurus) performance and pasture productivity. Pasture canopy characteristics, diet selection by grazing steers, and stand persistence from EG continuously grazed at Short, Medium, and Tall heights and two rotationally stocked treatments were compared with continuously stocked ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] (BG). The EG had proportionally more green leaf (78.2 vs. 24.5%), less stem (4.4 vs. 45.2%), less heads (0.4 vs. 5.6%), and similar dead tissue (17.0 vs. 24.8%). Plant fractions were similar in proportion among EG treatments. Digestible leaf mass was greater in EG than in BG (P < 0.01; 713 vs. 292 kg ha−1) and dominated the EG canopies with a linear (P < 0.01) increase in leaf mass with increasing FM (194–922 kg ha−1). Diets were similar in IVTOD (738 g kg−1), CP (151 g kg−1), and NDF (654 g kg−1) when continuously stocked but greater (P < 0.01) in IVTOD (791 g kg−1), and least in NDF (624 g kg−1) from the rotation. Stand declined linearly (P = 0.09) with decreasing FM (Tall = 34.5 and Short = 11.7% basal cover) but was similar between the two rotational systems (35.5%). Continuously stocking EG at about 38 cm gave greatest steer daily gain but rotations may prevent declines in stands with some sacrifice in gains.}, number={1}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Fisher, D. S.}, year={2010}, pages={179–186} }
 @article{burns_fisher_2010, title={Intake and Digestibility of Improved Selections of Tall Fescue and Orchardgrass Hays}, volume={50}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2009.03.0157}, abstractNote={ABSTRACT}, number={1}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S.}, year={2010}, pages={419–426} }
 @article{sauve_huntington_whisnant_burns_2010, title={Intake, Digestibility, and Nitrogen Balance of Steers Fed Gamagrass Baleage Topdressed at Two Rates of Nitrogen and Harvested at Sunset and Sunrise}, volume={50}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2009.02.0105}, abstractNote={ABSTRACT}, number={1}, journal={CROP SCIENCE}, author={Sauve, A. K. and Huntington, G. B. and Whisnant, C. S. and Burns, J. C.}, year={2010}, pages={427–437} }
 @article{burns_godshalk_timothy_2010, title={Registration of 'Colony' Lowland Switchgrass}, volume={4}, ISSN={["1936-5209"]}, DOI={10.3198/jpr2009.12.0722crc}, abstractNote={‘Colony’ (Reg. No. CV‐256, PI 658520) is a lowland cytotype of switchgrass (Panicum virgatum L.) developed and released by the USDA‐ARS and the North Carolina Agricultural Research Service. Colony was developed from three cycles of selection with random cross‐pollination occurring in cycle 0, index selection for forage dry matter yield and in vitro dry matter disappearance and crude protein concentrations in open‐pollinated isolation in cycles 1 and 2. Replicated yield trials were conducted for 5 yr in Piedmont and 4 yr in Coastal Plain soils of North Carolina. Associated nutritive value estimates were obtained for the last 3 yr from the Coastal Plain site. The quality of Colony hay was evaluated in replicated animal trials. Colony was released because of its greater dry matter concentration of cellulose and greater cellulose yield per hectare with potential for biomass purposes.}, number={3}, journal={JOURNAL OF PLANT REGISTRATIONS}, author={Burns, J. C. and Godshalk, E. B. and Timothy, D. H.}, year={2010}, month={Sep}, pages={189–194} }
 @article{xu_cheng_sharma-shivappa_burns_2010, title={Sodium Hydroxide Pretreatment of Switchgrass for Ethanol Production}, volume={24}, ISSN={["1520-5029"]}, DOI={10.1021/ef9014718}, abstractNote={Lignocellulose-to-ethanol conversion is a promising technology to supplement corn-based ethanol production. However, the recalcitrant structure of lignocellulosic material is a major obstacle to the efficient conversion. To improve the enzymatic digestibility of switchgrass for the fermentable sugar production in hydrolysis, sodium hydroxide pretreatment of the biomass feedstock was investigated. At 121, 50, and 21 °C, raw switchgrass biomass at a solid/liquid ratio of 0.1 g/mL was pretreated, respectively, for 0.25−1, 1−48, and 1−96 h at different NaOH concentrations (0.5, 1.0, and 2.0%, w/v). Pretreatments were evaluated based on the yields of lignocellulose-derived sugars in the subsequent enzymatic hydrolysis. At the best pretreatment conditions (50 °C, 12 h, and 1.0% NaOH), the yield of total reducing sugars was 453.4 mg/g raw biomass, which was 3.78 times that of untreated biomass, and the glucan and xylan conversions reached 74.4 and 62.8%, respectively. Lignin reduction was closely related to the ...}, number={3}, journal={ENERGY & FUELS}, author={Xu, Jiele and Cheng, Jay J. and Sharma-Shivappa, Ratna R. and Burns, Joseph C.}, year={2010}, month={Mar}, pages={2113–2119} }
 @article{burns_fisher_2010, title={Steer Performance and Pasture Productivity of Caucasian Bluestem at Three Forage Masses}, volume={102}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2009.0468}, abstractNote={The introduced perennial, warm‐season grass, Caucasian bluestem [Bothriochloa caucasia (Trin.) C.E. Hubbard ‘Caucasian’], appears to be adapted to the mid‐Atlantic region. This 4‐yr experiment compared animal and pasture productivity of Caucasian bluestem over three canopy heights, or forage masses (FM), designated as Short (14.6 cm), Medium (32.2 cm), and Tall (39.8 cm). The relationship of canopy height to diet and canopy characteristics was also evaluated. The soil was a Cecil clay loam (fine, kaolinitic, thermic Typic Kanhapludult). Pastures were continuously stocked using variable stocking from mid‐May through mid‐September. Forage mass (harvested to a 2.5‐cm stubble), increased linearly (P = 0.04) averaging 1.42, 2.31 and 2.75 Mg ha−1 for Short, Medium, and Tall canopy heights. Steer average daily gain (ADG) was similar among FM treatments (0.76 kg d−1) but weight gain decreased linearly (P < 0.01) from Short to Tall (from 817 to 518 kg ha−1). Increasing FM resulted in a quadratic decrease (P ≤ 0.04) in stocking rate (from 9.7 to 7.8 steers ha−1) and animal days (from 1019 to 700 d ha−1) and a linear decrease (P = 0.02) in effective feed units (from 4025 to 2806 kg ha−1). Stand counts of Caucasian bluestem increased linearly (P = 0.05) from Tall to Short FM (from 22.8–70.0%) with the Tall providing openings for potential weed invasion. Caucasian bluestem can be heavily stocked and may provide acceptable quality forage for summer grazing in the mid‐Atlantic region.}, number={3}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Fisher, D. S.}, year={2010}, pages={834–842} }
 @article{burns_wagger_fisher_2009, title={Animal and Pasture Productivity of 'Coastal' and 'Tifton 44' Bermudagrass at Three Nitrogen Rates and Associated Soil Nitrogen Status}, volume={101}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2008.0006x}, abstractNote={‘Coastal’ and ‘Tifton 44’ (T44) bermudagrass [Cynodon dactylon (L.) Pers.] are well adapted across the lower southern United States, but the grazing response of (T44) to N application in the Piedmont of the upper South warrants further evaluation. This 3‐yr experiment compared animal and pasture productivity of Coastal and T44 with three annual N rates of 101, 202, and 303 kg of N ha−1 on a Cecil clay loam (fine, kaolinitic thermic Typic Kanhapludult) soil typical of the Piedmont. Herbage mass differed for Coastal and T44 (3.5 and 3.0 Mg ha−1 respectively, P < 0.01), but not among N rates. The canopy of T44 was leafier (20.6 vs. 14.5% of dry matter) than Coastal and greater for in vitro true organic matter disappearance (IVTOD) (522 vs. 498 g kg−1) and CP (107 vs. 84 g kg−1) and lesser in NDF (596 vs. 605 g kg−1). The diet selected from T44 was greater in IVTOD (764 vs. 743 g kg−1) and lesser in NDF (596 vs. 605 g kg−1) giving greater steer average daily gain (0.63 kg vs. 0.57 kg; P < 0.01) which increased (P = 0.05) with N rate. Weight gain ha−1 (884 kg) and effective feed units (EFU) (4735 kg ha−1) were similar, and N rate linearly increased gain from 723 to 1073 kg ha−1 and EFU from 3978 to 5523 kg ha−1. Soil inorganic N was similar between cultivars but differed among soil depths. Tifton 44 pasture was greater in nutritive value, hence steer performance, and as productive as Coastal in the Piedmont.}, number={1}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Wagger, M. G. and Fisher, D. S.}, year={2009}, pages={32–40} }
 @article{cantrell_stone_hunt_ro_vanotti_burns_2009, title={Bioenergy from Coastal bermudagrass receiving subsurface drip irrigation with advance-treated swine wastewater}, volume={100}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2009.01.070}, abstractNote={Coastal bermudagrass (Cynodon dactylon L.) may be a potentially important source of bio-based energy in the southern US due to its vast acreage. It is often produced as part of a waste management plan with varying nutrient composition and energy characteristics on fields irrigated with livestock wastewater. The objective of this study was to determine the effect of subsurface drip irrigation with treated swine wastewater on both the quantity and quality of bermudagrass bioenergy. The treated wastewater was recycled from an advanced treatment system and used for irrigation of bermudagrass in two crop seasons. The experiment had nine water and drip line spacing treatments arrayed in a randomized complete block-design with four replicates. The bermudagrass was analyzed for calorific and mineral contents. Bermudagrass energy yields for 2004 and 2005 ranged from 127.4 to 251.4MJ ha(-1). Compared to irrigation with commercial nitrogen fertilizer, the least biomass energy density was associated with bermudagrass receiving treated swine wastewater. Yet, in 2004 the wastewater irrigated bermudagrass had greater hay yields leading to greater energy yield per ha. This decrease in energy density of wastewater irrigated bermudagrass was associated with increased concentrations of K, Ca, and Na. After thermal conversion, these compounds are known to remain in the ash portion thereby decreasing the energy density. Nonetheless, the loss of energy density using treated effluent via SDI may be offset by the positive influence of these three elements for their catalytic properties in downstream thermal conversion processes such as promoting a lesser char yield and greater combustible gas formation.}, number={13}, journal={BIORESOURCE TECHNOLOGY}, author={Cantrell, Keri B. and Stone, Kenneth C. and Hunt, Patrick G. and Ro, Kyoung S. and Vanotti, Matias B. and Burns, Joseph C.}, year={2009}, month={Jul}, pages={3285–3292} }
 @article{sauve_huntington_burns_2009, title={Effects of total nonstructural carbohydrates and nitrogen balance on voluntary intake of goats and digestibility of gamagrass hay harvested at sunrise and sunset}, volume={148}, ISSN={["1873-2216"]}, DOI={10.1016/j.anifeedsci.2008.03.001}, abstractNote={Abstract We evaluated differences in composition of Iuka gamagrass ( Tripsacum dactyloides L.) hay harvested at 06:00 (AM harvest) or 18:00 h (PM harvest), and measured how protein supplementation and time of harvest interact to affect the voluntary intake, digestibility, and N balance of goats. Boer cross wethers ( n  = 28; 24 kg) were randomly assigned to be fed supplement (310 g/kg of crude protein (CP), fed at 110 g/kg of dry matter (DM) intake, 14 goats) or no supplement (14 goats). Within supplemented or not supplemented groups, goats were randomly assigned to a crossover design of AM harvest (seven goats) or PM harvest (seven goats), and housed individually in metabolism crates with free access to water and mineral blocks. They were fed twice daily, with supplement offered 30 min prior to the morning feedings. After a 7-d adaptation, voluntary intake (goats were offered 1100 g/kg of previous day's intake) was measured for 14 d, followed by a 4-d adjustment phase to equalize DM offered between periods, and finally a 5-d digestion and balance phase. After Period 1, goats were switched to their new hay harvest times, and the protocol was repeated. Compared to the AM harvest, the PM harvest had higher (P versus 59.0 g/kg DM), monosaccharides (37.0 g/kg DM versus 28.6 g/kg DM), di- and polysaccharides (18.5 g/kg DM versus 15.4 g/kg DM) and less neutral detergent fiber (NDF, 700 g/kg versus 710 g/kg). Crude protein (79 g/kg DM) and starch (15.2 g/kg DM) were similar for the PM and AM harvest. Dry matter digestibility was higher (P versus AM harvests (555 g/kg DM versus 531 g/kg DM) and for supplemented versus not supplemented (563 g/kg DM versus 522 g/kg DM). Voluntary gamagrass DM intake (550 g/d versus 548 g/d) and calculated total digestible DM intake (327 g/d versus 313 g/d) were similar for the PM and AM harvest. However, total digestible DM intake during the digestion and balance phase was higher (P versus AM harvest (317 g/d versus 299 g/d). Time of harvest did not affect N intake, digestion, or calculated retention. Compared to no supplementation, the supplement improved (P versus 3.7 g/d) and retention (2.2 g/d versus 1.1 g/d). The PM harvest increased DM digested, largely TNC and digestible DM intake by goats due to increased TNC and not because of a 2% increase in DM intake. Providing a protein supplement had very limited effects on intake and digestibility of gamagrass.}, number={2-4}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Sauve, A. K. and Huntington, G. B. and Burns, J. C.}, year={2009}, month={Jan}, pages={93–106} }
 @article{burns_stone_hunt_vanotti_cantrell_fisher_2009, title={Intake and Digestibility of 'Coastal' Bermudagrass Hay from Treated Swine Waste Using Subsurface Drip Irrigation}, volume={38}, ISSN={["1537-2537"]}, DOI={10.2134/jeq2008.0493}, abstractNote={Waste handling systems for confined swine production in the upper South (approximately 32–37° N and 79–93° W) depend mainly on anaerobic lagoons and application of the waste effluent to cropland. The main objective of this study was to evaluate the quality of ‘Coastal’ bermudagrass [Cynodon dactylon (L.) Pers.] hay receiving effluent generated from a raw swine waste treatment system designed to reduce P and K concentrations and delivered by subsurface drip irrigation (SDI) compared with hay produced from commercial N fertilizer. Eight treatments, consisting of commercial N fertilizer or effluent, each irrigated at two irrigation rates (75 and 100% of estimated evapotranspiration) and two lateral spacings (0.6 and 1.2 m), were compared with a control treatment of commercial N fertilizer without irrigation. Three harvests were taken in each of 2 yr and five of the six evaluated using wether sheep (30–45 kg). Greatest dry matter intake (DMI) per unit body weight occurred for the control vs. all irrigated treatments (1.94 vs. 1.77 kg 100−1 kg; P = 0.02; SEM = 0.11). Among irrigated treatments, DMI was greatest from commercial N vs. effluent (1.81 vs. 1.71 kg 100−1 kg; P = 0.05; SEM = 0.11). Dry matter intake was similar for the 75% rate treatments and the non‐irrigated treatment (mean, 1.87 kg 100−1 kg) but was reduced for the 100% rate (1.94 vs. 1.72 kg 100−1 kg; P = 0.03; SEM = 0.11). Hay from the 75% rate was more digestible than hay from the 100% rate (527 vs. 508 g kg−1; P = 0.03; SEM = 21). The SDI system functioned well, and lateral spacing did not alter hay quality. Treated waste from a raw waste treatment system was readily delivered by SDI at the recommended rate to produce bermudagrass hay of adequate quality for ruminant production systems.}, number={4}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={Burns, J. C. and Stone, K. C. and Hunt, P. G. and Vanotti, M. B. and Cantrell, K. B. and Fisher, D. S.}, year={2009}, pages={1749–1756} }
 @article{yang_sharma-shivappa_burns_cheng_2009, title={Saccharification and Fermentation of Dilute-Acid-Pretreated Freeze-Dried Switchgrass}, volume={23}, ISSN={["1520-5029"]}, DOI={10.1021/ef9003335}, abstractNote={This study investigated the potential of three freeze-dried switchgrass germplasms (St6-1, St6-3E, and St6-3F) as whole plants or their stems and leaves for bioethanol production. Whole switchgrass germplasms contained 24.34−30.95% glucan, 14.68−18.58% xylan, and 17.39−19.46% lignin. Switchgrass samples were pretreated with dilute sulfuric acid at concentrations of 0.5, 1.0, or 1.5% (w/v) for 30, 45, or 60 min at 121 °C and 15 psi. Although lignin degradation was limited, over 80% hemicellulose solublization was observed, especially in leaf samples, and the removal could be enhanced by increasing the pretreatment intensity through acid concentration and treatment time adjustment. Within each germplasm, pretreated samples with the least lignin content or greatest percent hemicellulose (xylan and arabinan) solublization were hydrolyzed enzymatically by cellulase at 0, 15, or 30 filter paper units (FPU)/g of dry biomass supplemented with cellobiase. Although the addition of cellulase greatly improved cellulo...}, number={11}, journal={ENERGY & FUELS}, author={Yang, Ying and Sharma-Shivappa, Ratna R. and Burns, Joseph C. and Cheng, Jay}, year={2009}, month={Nov}, pages={5626–5635} }
 @article{huntington_magee_matthews_poore_burns_2009, title={Urea metabolism in beef steers fed tall fescue, orchardgrass, or gamagrass hays}, volume={87}, ISSN={["1525-3163"]}, DOI={10.2527/jas.2008-1444}, abstractNote={Two experiments were conducted to assess effects of endophyte treatments (Exp. 1), forage species (Exp. 2), and supplementation (Exp. 2) on urea production, excretion, and recycling in beef steers. Infusion of (15,15)N-urea and enrichment of urea in urine samples were used to calculate urea-N entry and recycling to the gut. Acceptably stable enrichment of (15)N-urea in urine was obtained after 50 h of intrajugular infusion of (15,15)N-urea, indicating that valid data on urea metabolism can be obtained from steers fed forages twice daily. After adjustment by covariance for differences in N intake among treatments in Exp. 1, steers fed endophyte-infected tall fescue had less (P<0.10) urea-N entry, recycling to the gut, and return of recycled urea-N to the ornithine cycle than those fed endophyte-free or novel endophyte-infected tall fescue. However, urea-N urinary excretion or return to the gut was similar among endophyte treatments when expressed as a proportion of urea-N entry. Urea-N entry and return to the gut in Exp. 2 was similar in steers fed gamagrass or orchardgrass hay after adjustment by covariance for differences in N intake. Less (P<0.01) urinary excretion, expressed as grams per day or as a proportion of urea-N entry, with gamagrass than with orchardgrass was associated with faster in vitro NDF-N digestion with gamagrass. Supplementation of gamagrass or orchardgrass with 1.76 kg/d of readily fermentable fiber and starch decreased urea entry (P<0.06) and urinary excretion of urea (P<0.01). Interactions between hay source and supplement reflected a greater response to supplementation for steers fed orchardgrass than for those fed gamagrass. After adjustment for differences among treatments in N supply, results of both experiments support the concept of improved N use in response to increased carbohydrate fermentability in the rumen, due either to inherent differences in forage fiber or to supplementation with readily fermentable carbohydrate (starch or fiber). Closer coordination of ruminal fermentation of carbohydrate and N sources provided greater and more efficient capture of dietary N as tissue protein in forage-fed steers.}, number={4}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Huntington, G. B. and Magee, K. and Matthews, A. and Poore, M. and Burns, J.}, year={2009}, month={Apr}, pages={1346–1353} }
 @article{burns_fisher_2008, title={'Coastal' and 'Tifton 44' bermudagrass availability on animal and pasture productivity}, volume={100}, ISSN={["0002-1962"]}, DOI={10.2134/agronj2007.0381}, abstractNote={Hybrid cultivars of bermudagrass [Cynodon dactylon (L.) Pers.] are a major feed source for ruminants across the southeastern United States. This 4‐yr experiment compared animal and pasture performance of ‘Coastal’ and ‘Tifton 44’ bermudagrasses over three canopy heights designated as short (5.6 cm), medium (10.1 cm), and tall (13.1 cm). The relationship of canopy height to ingestive mastication and canopy characteristics was also studied. Soil was a Cecil clay loam (clayey, Kaolinitic thermic Typic Hapludult). Pastures were continuously stocked using variable stocking to maintain the targeted canopy heights. Herbage mass (to soil surface) was similar between Coastal and Tifton 44 (T44) within each canopy height averaging 2.36, 4.08, and 5.25 Mg ha−1. Steer average daily gain (ADG) was greater (P = 0.09) from T44 than Coastal (0.58 vs. 0.51 kg) but no differences were noted in pasture productivity. Increasing herbage mass linearly increased (P < 0.01) ADG (0.40–0.59 kg) but reduced (P < 0.01) stocking rate (16.1–11.2 steers ha−1), which influenced animal days (1810–1079 d ha−1), weight gain (1057–786 kg ha−1), and effective feed units (6392–4452 kg ha−1). Steer ADG increased (P = 0.01) from short to medium canopy height (0.40–0.64 kg) with little change between medium and tall canopy height (0.64–0.59 kg). Tifton 44 pasture is of greater quality than Coastal giving greater ADG but both were productive producing about 1100 kg of gain ha−1 when effectively managed and utilized.}, number={5}, journal={AGRONOMY JOURNAL}, author={Burns, J. C. and Fisher, D. S.}, year={2008}, pages={1280–1288} }
 @misc{burns_2008, title={ASAS Centennial Paper: Utilization of pasture and forages by ruminants: A historical perspective}, volume={86}, ISSN={["1525-3163"]}, DOI={10.2527/jas.2008-1240}, abstractNote={Pastures, forages, and grasslands dominate the landscape across the United States and support a large ruminant population that supplies the nation with value-added animal products. A historical perspective is presented of the innovations as they occurred in the Journal of Animal Science over the past 100 yr in pasture and forage research. Consideration was given to both animal and pasture perspectives. Areas given consideration from the animal perspective were schemes for feedstuff analysis, experimental design and statistics, forage sample preservation, indirect methods of measuring intake and digestion, TDN and energy, nutritive value, harvested forage, and innovations in the grazing environment. Areas given consideration from the forage perspective were a framework for forage-animal interface research, determining pasture yield, choice of stocking method, grazing management, partitioning of forage DM, near-infrared reflectance spectroscopy technology, antiquality constituents, and forage sample preservation. Finally, the importance was discussed of applying research results from the forage-animal interface to general ruminant nutrition research beyond the interface that is focused on altered diets.}, number={12}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Burns, J. C.}, year={2008}, month={Dec}, pages={3647–3663} }
 @article{fellner_burns_marshall_2008, title={Effect of feeding corn, hull-less or hulled barley on fermentation by mixed cultures of ruminal microorganisms}, volume={91}, ISSN={["0022-0302"]}, DOI={10.3168/jds.2007-0078}, abstractNote={Increased demands for corn grain warrant the evaluation of alternative grain types for ruminant production systems. This study was conducted to determine the effects of hulled and hull-less barley (Hordeum vulgare L.) cultivars compared with corn (Zea mays L.) as an alternative grain type on fermentation in cultures of mixed ruminal microorganisms. Three continuous fermentors were fed 14 g of dry feed per day (divided equally between 2 feedings) consisting of alfalfa (Medicago sativa L.) hay pellets (40% of dry matter) and 1) ground corn, 2) hulled barley, or 3) hull-less barley concentrate (60% of dry matter) in each fermentor. Following an adaptation period of 5 d, culture samples were taken at 2 h after the morning feeding on d 6, 7, and 8 of each period for analysis. A second run of the fermentors followed the same treatment sequence to provide replication. Culture pH was reduced with corn (5.55) and did not differ between barley cultivars (average pH 5.89). Total volatile fatty acid concentration and acetate to propionate ratio were not different across grain type or barley cultivar with the exception of greater total volatile fatty acid concentrations with hull-less barley. Corn produced less methane (14.6 mmol/d) and ammonia-N (7.3 mg/100 mL) compared with barley (33.1 mmol/d and 22 mg/100 mL, respectively); methane was greater with hull-less barley but ammonia-N concentration was similar between the 2 barley cultivars. Hull-less barley had greater digestibility compared with hulled barley, and corn had reduced digestibility compared with barley. Concentrations of C18:0 were greater and those of C18:1 and C18:2 lesser in cultures fed hulled and hull-less barley compared with corn. Our data indicate that grain type and barley cultivar have an impact on ruminal fermentation. The lesser starch concentration of barley minimized the drop in culture pH and improved digestibility.}, number={5}, journal={JOURNAL OF DAIRY SCIENCE}, author={Fellner, V. and Burns, J. C. and Marshall, D. S.}, year={2008}, month={May}, pages={1936–1941} }
 @inproceedings{yang_sharma_burns_cheng_2008, title={Hydrolysis and fermentation of new switchgrass germplasm for bioethanol production}, volume={083799}, booktitle={Proceedings of the ASABE Annual International Meeting (Providence, Rhode Island)}, author={Yang, Y. and Sharma, R. R. and Burns, J. C. and Cheng, J. J.}, year={2008} }
 @inproceedings{xu_cheng_sharma-shivappa_burns_2008, title={Lime pretreatment of switchgrass for bioethanol production}, volume={083998}, DOI={10.13031/2013.24815}, abstractNote={Lignocellulose-to-ethanol conversion is a promising technology to supplement corn-based ethanol production. To improve the enzymatic digestibility of lignocellulosic materials, pretreatment is necessary as it alters the structure of lignocellulosic matrix, thereby making the cellulose more accessible to cellulase enzymes during hydrolysis. In this research, switchgrass was used as lignocellulosic feedstock and lime was used as pretreatment agent to study the impact of lime loading, residence time and temperature on the reducing sugar yield of biomass after pretreatment. The results showed that lime pretreatment could effectively improve the digestibility of switchgrass at both high temperature and low temperature. At 121oC, increasing lime loading or extending residence time didn’t necessarily favor the improvement of biomass digestibility. 15 min pretreatment with the lime loading of 0.10 g/g raw biomass was recommended. At 50oC, longer residence times were needed while the lime requirement didn’t change. 24 h pretreatment with the lime loading of 0.10 g/g raw biomass was recommended. Using the recommended conditions, the reducing sugar yields of pretreated biomass were over 4 times that of unpretreated biomass. The research also showed that lime pretreatment was promising at even lower temperatures. At ambient temperature, the total reducing sugar yield from raw biomass reached 392 mg/g raw biomass after 24 h lime pretreatment, only 8% lower than that obtained under the recommended condition at 121oC or 50oC.}, booktitle={Proceedings of the ASABE Annual International Meeting (Providence, Rhode Island)}, author={Xu, J. and Cheng, Jay and Sharma-Shivappa, R. R. and Burns, J. C.}, year={2008} }
 @article{vibart_fellner_burns_huntington_green_2008, title={Performance of lactating dairy cows fed varying levels of total mixed ration and pasture}, volume={75}, ISSN={["1469-7629"]}, DOI={10.1017/S0022029908003361}, abstractNote={Two, 8-week experiments, each using 30 lactating Holstein cows, were conducted to examine performance of animals offered combinations of total mixed ration (TMR) and high-quality pasture. Experiment 1 was initiated in mid October 2004 and Experiment 2 was initiated in late March 2005. Cows were assigned to either a 100% TMR diet (100:00, no access to pasture) or one of the following three formulated partial mixed rations (PMR) targeted at (1) 85% TMR and 15% pasture, (2) 70% TMR and 30% pasture and (3) 55% TMR and 45% pasture. Based on actual TMR and pasture intake, the dietary TMR and pasture proportions of the three PMR in Experiment 1 were 79% TMR and 21% pasture (79:21), 68% TMR and 32% pasture (68:32), and 59% TMR and 41% pasture (59:41), respectively. Corresponding proportions in Experiment 2 were 89% TMR and 11% pasture (89:11), 79% TMR and 21% pasture (79:21) and 65% TMR and 35% pasture (65:35), respectively. Reducing the proportion of TMR in the diets increased pasture consumption of cows on all PMR, but reduced total dry matter intake compared with cows on 100:00. An increase in forage from pasture increased the concentration of conjugated linoleic acids and decreased the concentration of saturated fatty acids in milk. Although milk and milk protein yields from cows grazing spring pastures (Experiment 2) increased with increasing intakes of TMR, a partial mixed ration that was composed of 41% pasture grazed in the fall (Experiment 1) resulted in a similar overall lactation performance with increased feed efficiency compared to an all-TMR ration.}, number={4}, journal={JOURNAL OF DAIRY RESEARCH}, author={Vibart, Ronaldo E. and Fellner, Vivek and Burns, Joseph C. and Huntington, Gerald B. and Green, James T., Jr.}, year={2008}, month={Nov}, pages={471–480} }
 @article{fisher_burns_2008, title={Testing for variation in animal preference for Jesup tall fescue hays with wild-type, novel, or no fungal endophyte}, volume={48}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2007.10.0548}, abstractNote={Tall fescue [Schedonorus phoenix (Scop.) Holub.] is an important source of forage but often contains a fungal endophyte [Neotyphodium coenophialum (Morgan‐Jones and Gams) Glenn, Bacon, and Hanlin] that can produce alkaloids and decrease animal performance. Removing the endophyte can reduce agronomic performance and persistence. An improved cultivar (‘Jesup’) with a novel (nontoxic) endophyte (trademark “MaxQ”) has improved agronomic performance. Persistence may be related to agronomic traits and animal feeding preferences. We tested for variation in animal preference among two harvests by testing each of three hays made from Jesup tall fescue that varied in endophyte status (no endophyte, containing the novel endophyte, or containing a wild‐type endophyte that produces alkaloids associated with toxicosis). We tested for preference using goats (Capra hircus), sheep (Ovis aries), and cattle (Bos taurus). All possible pairs were tested using traditional analysis of variance as well as multidimensional scaling. Multidimensional scaling of the animal preferences indicated that two dimensions were being used to rank the hays. The first dimension for all three animal species was related to variation in forage nutritive value. The second dimension was not correlated with any of the measured variables. Endophyte status was not a factor in the preferences expressed by the three animal species. It appears that no effective feedback mechanism exists related to endophyte status.}, number={5}, journal={CROP SCIENCE}, author={Fisher, D. S. and Burns, J. C.}, year={2008}, pages={2026–2032} }
 @article{huntington_burns_2008, title={The interaction of harvesting time of day of switchgrass hay and ruminal degradability of supplemental protein offered to beef steers}, volume={86}, ISSN={["0021-8812"]}, DOI={10.2527/jas.2006-701}, abstractNote={The objective of this study was to evaluate an interaction between harvest at 0600 (AM) vs. 1800 (PM) with high (HI) or low (LO) ruminal degradability of a protein supplement to change voluntary intake, digestion, or N retention by steers offered switchgrass (Panicum virgatum L.) hay. Black steers (255 +/- 14 kg of BW) were blocked by BW, and then randomly assigned (5 steers each) to AM/HI, PM/HI, AM/LO, or PM/LO treatment groups. Steers were group-housed in covered, outdoor pens with individual feeding gates. After adaptation and standardization, intake was measured for 21 d followed by a digestion trial (5 d of total collection). Steers were offered 767 (LO) or 825 (HI) g/d of supplement to provide 268 g of CP/d. Compared with AM, PM had greater (P = 0.01) concentrations of total nonstructural carbohydrate (TNC, 71 vs. 56 g/kg of DM), and lesser concentrations of NDF (760 vs. 770 g/kg of DM, P = 0.02), ADF (417 vs. 427 g/kg of DM, P = 0.02), and CP (55.9 vs. 58.6 g/ kg of DM, P = 0.07). Protein fractions A, B(2), and B(3) were similar for AM and PM, but HI contained more (P < 0.02) A (694 vs. 296 g/kg of protein) and less B(2) (174 vs. 554 g/kg of protein) fraction than LO. Harvest interacted with supplement to increase (P = 0.07) ad libitum digestible DMI for steers offered PM/HI (11.4 g/kg of BW daily) compared with steers offered PM/LO (10.2 g/kg of BW daily), but there was no difference for steers offered AM/LO or AM/HI (10.7 g/kg of BW). Apparent digestibilities of DM (594 vs. 571 g/kg of intake), NDF (591 vs. 562 g/kg of intake), ADF (585 vs. 566 g/kg of intake), and N (651 vs. 632 g/kg of intake) were greater (P < 0.04) for PM than for AM. Apparent digestibility of N was greater (P = 0.02) for HI (652 g/ kg of intake) vs. LO (631 g/kg of intake). Interactions between harvest and supplement for apparent digestibilities of NDF (P = 0.09) and ADF (P = 0.03) were due to no change or an increase in digestibility in response to increased ruminal degradability of supplement in steers offered PM harvest, whereas increased ruminal degradability of supplement decreased digestibility of NDF and ADF in steers offered AM harvest. Treatments did not affect hay intake (3.93 kg/d), N retained (15.8 g/d), or plasma urea N (5.25 mM) during ad libitum intake. Greater TNC in PM vs. AM harvest was not sufficient by itself to increase total voluntary DMI, but greater protein degradability interacted with harvest time to increase ruminal fiber digestibility and digestible DMI of beef steers offered PM vs. AM harvest.}, number={1}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Huntington, G. B. and Burns, J. C.}, year={2008}, month={Jan}, pages={159–166} }
 @inproceedings{xu_chen_wang_sharma-shivappa_burns_cheng_2007, title={Alkaline pretreatment of switchgrass for bioconversion to ethanol}, booktitle={2007 ASABE Regional Annual Conference (Fletcher, North Carolina)}, author={Xu, J. and Chen, Y. and Wang, Z. and Sharma-Shivappa, R. R. and Burns, J. C. and Cheng, J. J.}, year={2007} }
 @article{burns_fisher_mayland_2007, title={Diurnal shifts in nutritive value of alfalfa harvested as hay and evaluated by animal intake and digestion}, volume={47}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2007.02.0072}, abstractNote={Forages accumulate nonstructural carbohydrates during the day, with animals showing preference and improved daily responses from afternoon compared with morning cut hays. This study evaluated alfalfa (Medicago sativa L.) hay harvested at 0700, 1000, 1300, 1600, and 1900 h to determine how nutritive value changes during the day and to assess the impact of these changes on animal preference using cattle (Bos taurus L.), sheep (Ovis aries L.), and goat (Capra hircus L.) responses. Total nonstructural carbohydrates were altered by time of cut (cubic contrast, P < 0.01) ranging from 85 g kg−1 at 0700 h to 83 g kg−1 at 1000 h, then increasing to 97 g kg−1 by 1600 h with little change at 1900 h (96 g kg−1). Fiber fractions also varied diurnally, with a quadratic decrease from 418 g kg−1 at 0700 h to 387 g kg−1 by 1900 h in neutral detergent fiber. A combined analysis of three animal trials showed a linear increase in dry matter intake (DMI) with later hay harvest, a cubic response for dry matter digestion (DMD), and a linear increase in digestible DMI. Mean DMI increased from 27.5 g kg−1 body weight at 0700 h to a maximum of 30.8 g kg−1 body weight at 1600 h, whereas DMD decreased from 658 g kg−1 at 0700 to 647 g kg−1 at 1300 h and peaked at 664 g kg−1 at 1600 h. Digestible DMI increased from 18.1 g kg−1 body weight at 0700 h to a maximum of 20.5 g kg−1 body weight at 1600 h. No additional advantages in animal responses were noted by cutting after 1600 h.}, number={5}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S. and Mayland, H. F.}, year={2007}, pages={2190–2197} }
 @article{burns_fisher_2007, title={Dry matter intake and digestibility of 'Coastal', 'Tifton 44', and 'Tifton 85' bermudagrass hays grown in the US upper south}, volume={47}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci06.04.0253}, abstractNote={ABSTRACT}, number={2}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S.}, year={2007}, pages={795–810} }
 @inproceedings{keshwani_cheng_li_burns_chiang_2007, title={Microwave pretreatment of switchgrass to enhance enzymatic hydrolysis}, volume={077127}, DOI={10.13031/2013.23472}, abstractNote={Switchgrass is a promising lignocellulosic biomass for fuel-ethanol production. However, pretreatment of lignocellulosic materials is necessary to improve its susceptibility to enzymatic hydrolysis. The objectives of this study were to examine the feasibility of microwave pretreatment to enhance enzymatic hydrolysis of switchgrass and to determine the optimal pretreatment conditions. Switchgrass samples immersed in water, dilute sulfuric acid and dilute sodium hydroxide solutions were exposed to microwave radiation at varying levels of radiation power and residence time. Pretreated solids were enzymatically hydrolyzed and reducing sugars in the hydrolysate were analyzed. Microwave radiation of switchgrass at lower power levels resulted in more efficient enzymatic hydrolysis. The application of microwave radiation for 10 minutes at 250 watts to switchgrass immersed in 3% sodium hydroxide solution (w/v) produced the highest yields of reducing sugar. Results were comparable to conventional 60 minute sodium hydroxide pretreatment of switchgrass. The findings suggest that combined microwave-alkali is a promising pretreatment method to enhance enzymatic hydrolysis of switchgrass.}, booktitle={Proceedings of the ASABE Annual International Meeting (Minneapolis, Minnesota)}, author={Keshwani, D. R. and Cheng, J. J. and Li, L. and Burns, J. C. and Chiang, V.}, year={2007} }
 @article{griggs_macadam_mayland_burns_2007, title={Temporal and vertical distribution of nonstructural carbohydrate, fiber, protein, and digestibility levels in orchardgrass swards}, volume={99}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2006.0036}, abstractNote={Herbage nonstructural carbohydrates (NC) contribute to livestock performance and silage fermentation. Knowledge of the distribution patterns of NC and other nutritional constituents in orchardgrass (Dactylis glomerata L.) swards could support harvest management decisions. Our objective was to determine diurnal and vertical patterns of total NC (TNC), crude protein (CP), and neutral detergent fiber (NDF) concentrations, and in vitro true dry matter digestibility (IVTDMD) and NDF digestibility (NDFD) in orchardgrass swards in October, June, and August. Herbage was sampled at 6‐h intervals between 0100 and 1900 h from horizons positioned 40 to 27, 27 to 18, 18 to 12, and 12 to 8 cm above soil surface. Herbage composition varied among horizons in all months, and diurnally only in June and August. In June and August, only TNC with maxima of 109 to 123 g kg−1 at 1900 h exhibited consistent diurnal patterns. Swards harvested to residual heights of 18, 12, or 8 cm exhibited little spatial variation in TNC during June and August, but CP, NDF, and IVTDMD varied with harvest depth on all dates. As swards were harvested to successively greater depths, TNC increased in October, but not in June and August. In contrast, CP and IVTDMD decreased, and NDF increased, for harvests to successively greater depths in all months. For harvests in June and August, manipulation of depth would capture more variation in CP, NDF, and IVTDMD, but manipulation of time of day of harvest would capture more variation in TNC to meet animal performance and silage fermentation requirements.}, number={3}, journal={AGRONOMY JOURNAL}, author={Griggs, Thomas C. and MacAdam, Jennifer W. and Mayland, Henry F. and Burns, Joseph C.}, year={2007}, pages={755–763} }
 @article{huntington_burns_archibeque_2007, title={Urea metabolism in beef steers grazing Bermudagrass, Caucasian bluestem, or gamagrass pastures varying in plant morphology, protein content, and protein composition}, volume={85}, ISSN={["0021-8812"]}, DOI={10.2527/jas.2006-597}, abstractNote={Pastures of Bermudagrass (Cynodon dactylon, BG), Caucasian bluestem (Bothriochloa caucasica, CBS), and gamagrass (Tripsacum dactyloides, GG) were evaluated from the perspectives of forage composition, selection during grazing, and N metabolism in beef steers. All pastures were fertilized with 78 kg/ha of N approximately 60 and 30 d before sample collection. In 2000 and 2001, 12 steers (250 kg of BW) were blocked based on BW and then assigned randomly to a replicated, randomized complete block design, with 2 pastures of each forage and 2 steers per pasture. Three other steers with esophageal fistulas were used to collect masticate samples to represent intake preferences. Herbage mass was >1,900 kg/ha. After at least 14 d of adaptation, urine and blood samples were collected for determination of serum urea N and percentage of urinary N in the form of urea. One steer per pasture (6 steers per year) was infused i.v. with (15,15)N urea for 50 h before collecting urine for 6 h to measure urea N enrichment, urea entry rate, urinary urea excretion, gut urea recycling, and return of urea N to the ornithine cycle. The canopy leaf:stem DM ratio differed (P = 0.01) among BG (0.50), CBS (1.01), and GG (4.00). Caucasian bluestem had less CP (% of DM) than GG or BG in the canopy (9.6 vs. 12.0 or 12.3, P = 0.07) and in the masticate (9.8 vs. 14.7 or 13.9, P = 0.04). Bermudagrass had less true protein (% of CP) than CBS or GG in the canopy (72.9 vs. 83.3 or 83.0, P = 0.07) and in the masticate (73.7 vs. 85.8 or 88.0, P = 0.04). Compared with GG and BG, CBS had less serum urea N (10.1 or 12.2 vs. 2.5 mM, P = 0.01), urea entry rate (353 or 391 vs. 209 mmol of N/h, P = 0.07), and urinary urea excretion (105 or 95 vs. 18 mmol of N/h, P = 0.04), and a greater return of urea N to the ornithine cycle as a proportion of gut urea recycling (0.109 or 0.118 vs. 0.231, P = 0.02). Urea production and recycling in these steers responded more to the N concentration in the grasses than to differences in plant protein fractions. There was no evidence of improved N capture by the steers due to changes in the leaf:stem ratio among the grasses at the herbage mass evaluated.}, number={8}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Huntington, G. B. and Burns, J. C. and Archibeque, S. L.}, year={2007}, month={Aug}, pages={1997–2004} }
 @misc{nelson_burns_2006, title={Fifty years of grassland science leading to change}, volume={46}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2006.04.0278gas}, abstractNote={Division C‐6 was established in 2000, but members associated with forages and grazinglands have been active in the Crop Science Society of America (CSSA) since its inception; 21 have served as President and many authored textbooks and comprehensive reference works. Complex forage and pasture mixtures were common in 1955, but shifted to monocultures in the 1960s and 1970s. Mixtures returned in the 1980s as N prices increased, broader values of legumes became known, nutritive value was better understood, and environmental issues increased. Alfalfa (Medicago sativa L.) for dairy production had strong leadership from the private sector in seed production and breeding. Tall fescue (Festuca arundinacea Schreb.) was well‐adapted, conserved soil, and extended grazing in the transition zone to increase beef cow–calf production. Bermudagrass [Cynodon dactylon (L.) Pers.] benefited from vegetative propagation, conserved soil, and was improved for adaptation, yield, and nutritive value. Yield advancements, except for a few species, have been discouraging. Management benefited from advances in disease resistance, methods for assessing nutritive value, and understanding the role of endophytic fungi. Modest increases in nutritive value, coupled with improved pasture management, have increased animal performance. Emerging interests include biomass, carbon sequestration, and roles of biodiversity. Molecular techniques offer potential to better understand the plants and make genetic progress.}, number={5}, journal={CROP SCIENCE}, author={Nelson, C. Jerry and Burns, J. C.}, year={2006}, pages={2204–2217} }
 @article{burns_fisher_rottinghaus_2006, title={Grazing influences on mass, nutritive value, and persistence of stockpiled Jesup tall fescue without and with novel and wild-type fungal endophytes}, volume={46}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2005.09-0327}, abstractNote={Introducing novel endophytes into tall fescue (Festuca arundinaceaSchreb.) that produce no ergot alkaloids could prevent negative impacts on animal performance while improving plant persistence. This 3‐yr study evaluated ‘Jesup’ tall fescue (TF) for forage mass, nutritive value, and stand persistence when containing no endophyte, a novel endophyte (no ergot alkaloids), or a wild‐type endophyte (ergot alkaloids). Forage was accumulated from mid‐August and treatments consisted of (i) a grazed control (grazed when growth approximated 10 to 15 cm), or forage accumulated and grazed in (ii) mid‐November, (iii) mid‐December, (iv) mid‐January, and (v) mid‐February. Endophyte status had no influence on total forage mass; forage removed by grazing; proportion of leaf, stem, and dead fractions; or on nutritive value (except ergovaline which was greatest in the wild type). Delaying defoliation linearly reduced forage mass, ergovaline concentration, and nutritive value. All stands of TF declined with losses similar (P= 0.37) for wild‐type and novel stands (29 vs. 42%) but were greatest for the TF without an endophyte (29 vs. 75%;P= 0.01 and 42 vs. 75%;P= 0.04). These data support the use of novel endophytes in TF for animal production and caution against the use of endophyte‐free TF because of decreased stand longevity. The presence of ergovaline can be minimized by stockpiling TF with utilization after late autumn but occurs with a sacrifice in forage mass and nutritive value.}, number={5}, journal={CROP SCIENCE}, author={Burns, J. C. and Fisher, D. S. and Rottinghaus, G. E.}, year={2006}, pages={1898–1912} }
 @misc{burns_2006, title={Grazing research in the humid east: A historical perspective}, volume={46}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2005.0185}, abstractNote={A historical perspective of the major developments in grazing research for the humid Eastern USA was addressed. Consideration was given to the emergence of the area of grazing research relative to the initial structure of agricultural institutions, the orientation of scientist within the constraints of the institutional boundaries (departments) and the carry‐through noted today. Early grazing research was constrained to the informal literature and discussed as informational, demonstrational, and experimental. The milestones that have been achieved, including statistical application, conceptual assessment, description of grazing management, methods of computing pasture yields, the origin and use of put‐and‐take stocking, pasture and animal biomass relationships, choice of stocking method, flexible grazing, and measurements in recent grazing research are presented and discussed relative to their origin and application. Furthermore, consideration was given to a number of important innovations with origin in the humid East that have contributed to the advancement of grazing research. Finally, brief consideration is given to future priority areas of grazing research and associated constraints.}, number={1}, journal={CROP SCIENCE}, author={Burns, JC}, year={2006}, pages={118–130} }
 @article{burns_fisher_2006, title={Intake and digestion of 'Jesup' tall fescue hays with a novel fungal endophyte, without an endophyte, or with a wild-type endophyte}, volume={46}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2005.04-0040}, abstractNote={Tall fescue (Festuca arundinaceaSchreb.) is an important forage resource for beef (Bos taurusL.) production in the North–South transition zone. Recently, the cultivar ‘Jesup’ was released to provide improved stand survival when infected with a novel (nontoxic) endophyte marketed as MaxQ (Pennington Seed, Madison, GA), and warrants evaluation as a source of winter hay for beef cattle. Intake and digestion experiments were conducted to evaluate Jesup tall fescue containing the MaxQ endophyte (presumably without ergot alkaloids), Jesup with no endophyte, and Jesup with a wild‐type endophyte capable of producing ergot alkaloids. Initial growth of the three endophyte treatments was harvested in April and a regrowth harvested in June. These six hays were fed to goats (Capra hircusL.) and sheep (Ovis ariesL.). The hays harvested in June were also fed to cattle. The digestibility of the endophyte treatments was similar but goats had greater daily dry matter intake when fed MaxQ compared with wild‐type hay (2.63 vs. 2.43 kg 100−1kg body weight;P= 0.07) while intake was similar to the endophyte‐free hay. Sheep consumed hays similarly, regardless of harvest date, as did steers fed the June harvest. Daily intake of hays harvested in April and June were similar for goats, whereas sheep consumed more of the April hays (2.89 vs. 2.57 kg 100−1kg body weight;P< 0.01) and both digested the April hays to a greater extent. Endophyte status of the hays had little influence on their quality.}, number={1}, journal={CROP SCIENCE}, author={Burns, JC and Fisher, DS}, year={2006}, pages={216–223} }
 @article{burns_mayland_fisher_2005, title={Dry matter intake and digestion of alfalfa harvested at sunset and sunrise}, volume={83}, DOI={10.2527/2005.831262x}, abstractNote={The preference exhibited by animals in selecting one feed over another is important only if the preferred diet is consumed daily in larger quantities, digested to a greater extent, or both. Six alfalfa (Medicago sativa L.) hays were harvested in pairs at sunset (PM) and sunrise (AM) on consecutive days at three harvest dates. A previous study of these hays demonstrated differences in ruminant preference favoring PM harvests. This study evaluated the effects of time of cutting and harvest date on voluntary DMI and nutrient digestibility. The hays were field-cured, baled, and chopped before evaluation for intake and digestibility. Studies were conducted for sheep (Ovis aries), goats (Capra hircus), and cattle (Bos taurus). Goats, but not steers or sheep, demonstrated differences in nutrient digestibility between PM- and AM-cut hays. Goats consumed more PM than AM hay (2.97 vs. 2.83 kg/100 kg of BW; P = 0.07) and digested it to a greater extent (0.710 vs. 0.696; P = 0.03), resulting in greater digestible DMI (2.11 vs. 1.97 kg/100 kg of BW; P = 0.03). Sheep consumed (mean = 2.52 kg/100 kg of BW; P = 0.59) and digested (mean = 0.681; P = 0.25) PM- and AM-cut hays similarly. Steers consumed larger quantities of PM-than AM-cut hay (2.90 vs. 2.62 kg/100 kg of BW; P = 0.11), but digestion did not differ with cutting time (mean = 0.660; P = 0.75). Difference values (composition of fed hay minus composition of orts) indicated that sheep and goats selected from the feed offered similarly, whereas steers selected differently. Difference values for CP averaged 94 and 101 g/kg for goats and sheep and 32 g/kg for steers (P < 0.01), and difference values for NDF averaged 185 and 196 g/kg for goats and sheep and 73 g/kg for steers (P <or= 0.01). Steer DMI and digestible DMI were associated with preference (r = +0.83, P <or= 0.05; and r = +0.89, P <or= 0.05) and with coordinates for preference criteria (dimension 1; r = +0.90, P <or= 0.05; and r = +0.89, P <or= 0.05) from a previous preference trial. Intake and digestion responses for goats and sheep showed no relationship with the previous preference trial measurements. For cattle and goats, the management strategy of mowing in the afternoon seems to take advantage of small, but influential diurnal changes in the soluble carbohydrate fraction and offers the potential to improve forage quality.}, number={1}, journal={Journal of Animal Science}, author={Burns, J. C. and Mayland, H. F. and Fisher, D. S.}, year={2005}, pages={262–270} }
 @article{burritt_mayland_provenza_miller_burns_2005, title={Effect of added sugar on preference and intake by sheep of hay cut in the morning versus the afternoon}, volume={94}, ISSN={["1872-9045"]}, DOI={10.1016/j.applanim.2005.03.001}, abstractNote={Ruminants prefer hay cut in the afternoon to hay cut in the morning, presumably because hay cut in the afternoon contains higher concentrations of non-structural carbohydrates than hay cut in the morning. We determined if adding sugars (glucose and sucrose) to ground hay would account for differences in preference and affect intake of hay. Alfalfa hay cut either in the afternoon (PM) or the following morning (AM) was used in the trials. Glucose and sucrose were added to AM hay (AMS) to make its sugar content similar to PM hay. During the first trial, lambs received a choice of either: (1) AM and PM hay; (2) AMS and PM hay; or (3) AMS and AM hay. Lambs preferred PM to AMS or AM hay. We also studied how increasing the concentration of added sugars affected preference for hay. Lambs received a choice of AM hay and AM hay with either 1, 2, 3, or 4% added sugar. On the first day of the trial, lambs ate similar amounts of each hay type, regardless of the amount of sugar added. By the end of the trial, lambs preferred hay with 2, 3, or 4% added sugar compared with AM hay without added sugar. During the intake trial, lambs ate similar amounts of AM, AM hay with added starch and sugar (AMSS), and PM hay. After the intake trial, a final preference trial determined that prolonged exposure to AMSS hay increased preference for AMSS hay compared with AM hay. Our results indicate that preference for PM hay is likely related to increased levels of sugars, such as glucose and sucrose, and that lambs learn about the post-ingestive benefits of exogenous sugars added to hay.}, number={3-4}, journal={APPLIED ANIMAL BEHAVIOUR SCIENCE}, author={Burritt, EA and Mayland, HF and Provenza, FD and Miller, RL and Burns, JC}, year={2005}, month={Oct}, pages={245–254} }
 @article{magee_poore_burns_huntington_2005, title={Nitrogen metabolism in beef steers fed gamagrass or orchardgrass hay with or without a supplement}, volume={85}, ISSN={["1918-1825"]}, DOI={10.4141/a04-045}, abstractNote={ A 50:50 soybean hull:corn grain supplement fed at 0.75% of body weight (BW) decreased ad libitum gamagrass or orchardgrass hay intake by steers, but increased total dry matter (DM) intake, DM digestibility, N intake, and N retained. Supplementation had a greater effect on N metabolism in steers fed orchardgrass than steers fed gamagrass. Key words: Steers, beef, hulls, soybean, metabolism, nitrogen }, number={1}, journal={CANADIAN JOURNAL OF ANIMAL SCIENCE}, author={Magee, KJ and Poore, MH and Burns, JC and Huntington, GB}, year={2005}, month={Mar}, pages={107–109} }
 @article{griggs_macadam_mayland_burns_2005, title={Nonstructural carbohydrate and digestibility patterns in orchardgrass swards during daily defoliation sequences initiated in evening and morning}, volume={45}, ISSN={["1435-0653"]}, DOI={10.2135/cropsci2003.0613}, abstractNote={Herbage soluble carbohydrate (SC) levels vary diurnally and livestock intake can be higher for herbage harvested or allocated to animals in the evening than in the morning. Few assessments of SC and digestibility patterns have been made during sward depletion in rotationally stocked orchardgrass (Dactylis glomerata L.). We tested the hypothesis that simulated evening daily pasture allocation increases 24‐h mean herbage SC and digestibility levels relative to morning allocation. Total nonstructural carbohydrate (TNC) and in vitro true dry matter digestibility (IVTDMD) levels were compared during 24‐h clipping sequences initiated at 1900 h (PM) and 0700 h (AM). Sward height was progressively reduced from 40 to 8 cm at 6‐h intervals in October, June, and August. Successively lower horizons from defoliation sequences and also from control areas that were not under progressive defoliation were analyzed. Digestibility and TNC levels varied diurnally and seasonally, and were often higher for PM sequences, but differences among 24‐h means were small. Daily mean TNC levels for defoliation sequences initiated in PM and AM were 138 vs. 132, 93 vs. 88, and 72 vs. 60 g kg−1 in October, June, and August, respectively. In all periods, digestibility decreased from approximately 920 to 800 to 890 g kg−1 during sward depletion and displayed similar patterns between defoliation sequences. Patterns of TNC and digestibility during sward depletion may not be represented by those in intact swards, and PM allocation of daily herbage may not increase 24‐h mean dietary TNC density relative to AM allocation. Daily quantities of ingested TNC could be higher for PM herbage allocation if livestock consume proportionately more herbage in the PM than we simulated.}, number={4}, journal={CROP SCIENCE}, author={Griggs, TC and MacAdam, JW and Mayland, HF and Burns, JC}, year={2005}, pages={1295–1304} }
 @article{mehaffey_fisher_burns_2005, title={Photosynthesis and nutritive value in leaves of three warm-season grasses before and after defoliation}, volume={97}, ISSN={["1435-0645"]}, DOI={10.2134/agronj2004.0049}, abstractNote={Forage yields are influenced by plant response to defoliation. We examined the photosynthesis and nutritive value of first (first leaves) and third (third leaves) fully expanded leaves (numbered from the apex) in three warm‐season (C4) grasses. Net photosynthetic rates at uniform temperature and light both before and after a 2‐wk exposure to full sunlight and the effect of leaf position on nutritive value were determined on vegetative tillers in well‐established swards of bermudagrass [Cynodon dactylon L. (Per.) cv. Tifton 44], caucasian bluestem [Bothriochloa caucasica (Trin.) C.E. Hubb.], and Atlantic coastal panicgrass [Panicum amarum var. amarulum (Hitchcock and Chase) P.G. Palmer] growing on a Cecil clay loam (clayey, kaolinitic, thermic Typic Hapludults). Bermudagrass had the greatest level of crude protein (CP), followed by panicgrass and bluestem. Fiber was greater in the first leaves than in the third leaves for bermudagrass and panicgrass but not for bluestem. Photosynthetic rates of panicgrass and bluestem third leaves estimated 2 wk after defoliation of the surrounding canopy were less than estimates made before defoliation in the first leaves but were similar to the third leaves before canopy defoliation. The third leaves of bermudagrass 2 wk after defoliation had lesser photosynthetic rates per unit chlorophyll than the first or third leaves before defoliation. Photosynthetic rates were correlated with hemicellulose across leaf classes and species (r2 = 0.93). The photosynthetic decline observed in third leaves of bermudagrass compared with panicgrass and bluestem is evidence of variation in leaf response after defoliation among warm‐season grasses.}, number={3}, journal={AGRONOMY JOURNAL}, author={Mehaffey, MH and Fisher, DS and Burns, JC}, year={2005}, pages={755–759} }
 @article{fisher_burns_mayland_2005, title={Ruminant selection among switchgrass hays cut at either sundown or sunup}, volume={45}, DOI={10.2135/scropsci2004.0388}, number={4}, journal={Crop Science}, author={Fisher, D. S. and Burns, J. C. and Mayland, H. F.}, year={2005}, pages={1394–1402} }
 @article{burns_2005, title={Utilization by cattle, sheep, and goats of forage harvested from long-term Bermudagrass spray fields receiving swine lagoon effluent}, volume={21}, ISBN={1080-7446}, DOI={10.15232/s1080-7446(15)31232-8}, abstractNote={Bermudagrasses frequently serve as receivers of swine lagoon effluent in swine production confinement systems in the Southeast. This study evaluated DMI and digestion of field-chopped, dehydrated regrowth forage cut from mature Coastal bermudagrass spray fields following harvest in late July. Four treatments were evaluated in separate experiments each with cattle, sheep, and goats. The treatments consisted of forage harvested at 2 wk of regrowth and either fed chopped ( 2-WC ) or pelleted ( 2-WP ) and that harvested and pelleted at 3 wk ( 3-WP ) and 4 wk ( 4-WP ) of regrowth. The long-time established spray fields varied in the proportions of bermudagrass but averaged 45% for the 2-wk regrowth and 50% for the 4-wk regrowth; the balance was composed of annual grasses and broadleaved weeds. All three pelleted forages were readily consumed with DMI (kg/100 kg of BW) averaging 2.99 for steers, 4.35 for sheep, and 3.21 for goats. Steers and goats consumed all pelleted treatments similarly, whereas sheep consumed 2-WP and 3-WP similarly (4.41) but consumed less 4-WP (4.23) compared with 2-WP (4.49). Pelleting increased (P≤0.01) DMI compared with chopping (3.01 vs 2.16 ± 0.087 for steers, 3.29 vs 2.37 ± 0.071 for goats, and 4.49 vs 2.54 ± 0.072 for sheep). Steers and sheep digested 2-WP and 4-WP similarly and digested both at rates greater (P≤0.05) than 3-WP; goats digested all similarly (P=0.11). These short-term responses indicate that forages from mature bermudagrass fields sprayed with swine effluent have potential as a feed in ruminant production systems.}, number={5}, journal={Professional Animal Scientists}, author={Burns, J. C.}, year={2005}, pages={352} }
 @article{eun_fellner_burns_gumpertz_2004, title={Fermentation of eastern gamagrass (Tripsacum dactyloides [L.] L.) by mixed cultures of ruminal microorganisms with or without supplemental corn}, volume={82}, DOI={10.2527/2004.821170x}, abstractNote={Five dual-flow fermentors (700 mL) were used to determine the effects of eastern gamagrass (Tripsacum dactyloides [L.] L.) diets on microbial metabolism by mixed rumen cultures. Fermentors were incubated with filtered ruminal contents and allowed to adapt for 4 d to diets followed by 3 d of sample collection. Five dietary treatments were tested: 1) gamagrass hay (GH) + no corn (GHNC), 2) gama grass silage (GS) + no corn (GSNC), 3) GS + low corn (GSLC), 4) GS + medium corn (GSMC); and 5) GS + high corn (GSHC). The experiment was conducted as a randomized complete block design with five treatments and three replications. Total VFA concentrations were not affected by diets. Corn addition linearly decreased (P < 0.001) molar proportion of acetate. In contrast, molar proportion of propionate was reduced in GSLC (cubic effect, P < 0.001) but remained similar across other diets. Corn supplementation linearly increased molar proportion of butyrate (P < 0.001). The acetate + butyrate-to-propionate ratio was highest in cultures offered GSLC (cubic effect, P < 0.001) but similar across other diets. Feeding GSNC resulted in a higher ruminal pH compared with GHNC (P < 0.03). Increasing the level of corn supplementation in GS linearly decreased culture pH (P < 0.001). All diets resulted in similar methane production, with the exception of GSMC, which lowered methane output (quadratic effect, P < 0.004). Total substrate fermented to VFA and gas tended to be greater with GHNC than with GSNC (P < 0.06) and linearly increased with the addition of corn (P < 0.004). Neutral detergent fiber digestibility was similar between GH and GS and was not affected by supplemental corn. Microbial N flow increased in cultures offered GSHC (quadratic effect, P < 0.02). Corn supplementation at the medium and high level linearly decreased C 18:0 (P < 0.02) and increased trans-C18:1 (P < 0.004). Including corn at the high level with GS did not have a detrimental effect on fermentation in dual-flow fermentors.}, number={1}, journal={Journal of Animal Science}, author={Eun, J. S. and Fellner, Vivek and Burns, J. C. and Gumpertz, M. L.}, year={2004}, pages={170–178} }
 @article{stevens_burns_fisher_eisemann_2004, title={The  influence of high-nitrogen forages on the voluntary feed intake of sheep}, volume={82}, DOI={10.2527/2004.8251536x}, abstractNote={The objective of this research was to examine the effect of high concentrations of nonprotein nitrogen (NPN) on the voluntary food intake of sheep fed high-quality grasses. Wether lambs (n = 6 per treatment) were fed dried switchgrass (Panicum virgatum L.; Exp. 1) or dried tall fescue (Festuca arundinacea Schreb.; Exp. 2). In both experiments, urea was added to the dried forage at 0 (control), 12, or 24 g of N/kg of DM to increase the NPN concentration. Acid detergent fiber concentrations were 305 g/kg of DM in both experiments, although DM digestibility was 663 and 618 g/ kg of DM in Exp. 1 and Exp. 2, respectively. Voluntary feed intake of the control forage was 28.2 and 19.1 g/ kg of BW in Exp. 1 and Exp. 2, respectively, and decreased for the high-urea treatments to 25.2 and 16.2 g/kg of BW in Exp. 1 (P = 0.07) and Exp 2 (P = 0.03), respectively. Total feed N concentrations increased from 29.5 g to 45.7 g of N/kg of DM in Exp. 1 (P < 0.01) and from 28.4 to 55.9 g of N/kg of DM in Exp. 2 (P < 0.01). Nonprotein N concentrations increased from 28.3 to 53.8% of the total N in switchgrass diets (Exp. 1; P < 0.01), and from 26.4 to 64.0% in tall fescue diets (Exp. 2; P < 0.01). Plasma urea concentrations of the lambs increased from 3.1 to 6.6 mM (Exp. 1; P < 0.01) and from 2.9 to 5.8 mM (Exp. 2; P < 0.01) as the amount of urea added to the diets increased. These changes resulted in an increase in plasma osmolality from 298 to 307 mOsm/kg (Exp. 1; P = 0.04), and from 299 to 307 mOsm/kg (Exp. 2; P = 0.06). Increasing feed N and NPN concentrations through the addition of urea caused a significant decrease in the voluntary feed intake of sheep fed tall fescue and switchgrass. These responses showed no significant cause-and-effect relationship between voluntary feed intake, plasma urea concentrations, and plasma osmolality.}, number={5}, journal={Journal of Animal Science}, author={Stevens, D. R. and Burns, J. C. and Fisher, D. S. and Eisemann, J. H.}, year={2004}, pages={1536–1542} }
 @article{eun_fellner_burns_gumpertz_2003, title={Eastern gamagrass evaluated as hay or silage for lactating dairy cows}, volume={19}, ISBN={1080-7446}, DOI={10.15232/s1080-7446(15)31442-x}, abstractNote={Twenty lactating Holstein cows were used to determine the nutritional value of eastern gamagrass. Dietary treatments consisted of 1) gamagrass hay and no corn (HNC), 2) gamagrass silage (S) and no corn (SNC), 3) S and low corn (SLC), 4) S and medium corn (SMC), and 5) S and high corn (SHC). Gamagrass fed as hay or silage did not change (P>0.10) milk yield, but corn inclusion tended to increase (P<0.08) milk yield. Yields of milk protein (0.69 vs 0.80 kg/d), lactose (1.23 vs 1.44 kg/d), and solids-not-fat (2.12 vs 2.48 kg/d) tended to be greater for SNC than for HNC (P<0.08). Corn inclusion increased milk yields compared with SNC. Gamagrass fed as silage resulted in a greater feed conversion efficiency than did gamagrass fed as hay (2.16 vs 1.88; P<0.01). Adding corn to S reduced feed efficiency. Conversion of feed N to milk N was greater (P<0.01) for gamagrass fed as silage than for hay. Milk urea N (MUN) concentration was greater (P<0.01) for cows fed HNC than for cows on all other treatments. Feeding S significantly lessened MUN concentration. Including corn at the medium and high levels further reduced MUN concentration (P<0.05). Increased energy from corn at the high level increased milk yield and tended to increase conversion of feed N into milk protein. Gamagrass fed as silage without or with corn improved the N status of the cows, as indicated by lesser MUN concentrations.}, number={5}, journal={Professional Animal Scientists}, author={Eun, J. S. and Fellner, Vivek and Burns, J. C. and Gumpertz, M. L.}, year={2003}, pages={362} }
 @article{burns_chamblee_giesbrecht_2002, title={Defoliation intensity effects on season-long dry matter distribution and nutritive value of tall fescue}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.1274}, abstractNote={Implementation of intensive grazing management requires knowledge about pasture growth rates and nutritive value throughout the grazing season. Such information is lacking because results from small-plot defoliation experiments generally focus on annual dry matter yields (DMYs) and season mean nutritive value. In this experiment, the influences of defoliation treatments on daily growth rate (DGR) and associated nutritive value of tall fescue (Festuca arundinacea Schreb.) throughout the growing season were evaluated. A 3-yr study was conducted on a Typic Kanhapludult soil near Raleigh, NC. Eight defoliation treatments (31-, 15-, 10- and 8-cm canopy heights cut to a 5-cm stubble; 31-, 15-, and 11-cm canopy heights cut to a 9-cm stubble, and an 8-cm canopy height cut to a 4-cm stubble) were evaluated in a randomized complete block design. Daily growth rates (kg ha -1 ) were significantly (P ≤ 0.01) altered by defoliation treatments and by years within treatments. When rainfall was near normal in both spring and late summer, tall fescue growth rates, depending on defoliation treatment, ranged from 34 to 55 kg ha -1 d -1 in May, from 7 to 18 kg ha -1 d -1 in late July, to 22 to 35 kg ha -1 d -1 in late September. In less favorable years, DGRs seldom exceeded 30 kg ha -1 d -1 in the spring or 15 to 30 kg ha -1 d -1 in the autumn. Depending on defoliation treatments, in vitro dry matter disappearance (IVDMD) ranged between 650 and 733 g kg -1 in the spring, 479 and 687 g kg -1 in midsummer, and 549 and 807 g kg -1 by late summer. Crude protein (CP) and detergent fiber fraction concentrations were also examined. The approach used to estimate DGR and associated nutritive value changes throughout the growing season resulted in useful data that can be applied in developing intensive grazing management practices.}, number={4}, journal={CROP SCIENCE}, author={Burns, JC and Chamblee, DS and Giesbrecht, FG}, year={2002}, pages={1274–1284} }
 @article{heagle_burns_fisher_miller_2002, title={Effects of carbon dioxide enrichment on leaf chemistry and reproduction by twospotted spider mites (Acari : Tetranychidae) on white clover}, volume={31}, ISSN={["0046-225X"]}, DOI={10.1603/0046-225X-31.4.594}, abstractNote={Abstract Plant growth and yield responses to carbon dioxide (CO2) enrichment are well established. Much less is known of the response of arthropod pests to CO2 enrichment. Reproductive response of twospotted spider mites (Tetranychus urticae Koch) on white clover (Trifolium repens L.) to a range of CO2 concentrations was measured. The CO2 treatments were applied for 24 h d−1 at ≈395, 484, 570, 657, and 748 μLL−1 on the 14 d before and 26–27 d after infestation with mites. Eggs, larvae, nymphs, and adult mites were removed from leaves and counted 27–29 d after infestation. Leaf area and weight were measured, and leaves were analyzed to measure structural and nonstructural carbohydrates, N, amino acids and digestibility. Carbon dioxide enrichment caused linear increases in plant growth and foliar nonstructural carbohydrates, but caused linear decreases in foliar N. Carbon dioxide enrichment significantly increased the rate of mite reproduction on both clover clones. Correlations between mite population increase were significantly positive for foliar nonstructural carbohydrates and significantly negative for foliar N. Concentrations of ambient CO2 expected in the 21st century may increase the risk of mite population damage on some plant species.}, number={4}, journal={ENVIRONMENTAL ENTOMOLOGY}, author={Heagle, AS and Burns, JC and Fisher, DS and Miller, JE}, year={2002}, month={Aug}, pages={594–601} }
 @article{burns_sollenberger_2002, title={Grazing Behavior of ruminants and daily performance from warm-season grasses}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.0873}, abstractNote={An estimate of the animal-production potential of pastures can be assessed by knowing the daily dry matter (DM) intake of the grazing animal and the digestibility of the DM consumed. The objective of this paper is to examine the relationships between pasture canopy characteristics, ingestive behavior, and daily animal response from warm-season pastures. Of daily DM intake and digestibility of the DM consumed, the former is the most variable and the most difficult to determine. One approach to estimating daily DM intake has been to use the components of ingestive behavior to determine a short-term intake rate (g min−1), which can be scaled using grazing time (min d−1) to give a 24-h DM intake (kg d−1). This approach has been used experimentally with some success, but has not found application in production settings. While aspects of ingestive behavior, including ingestive mastication, are common to all grazing ruminants, literature indicates that differences occur among ruminant species and that animals ingest different pasture species differently. This results in plant-animal interactions. Frequently these dynamics are not clearly addressed for cool-season and warm-season pastures in literature reviews, which adds undue confusion to the general area. Ingestive behavior is discussed relative to animal- and pasture-generated bounds which operate within paddocks and can greatly alter ingestive behavior estimates. Also presented are relationships between diet particle size, associated with ingestive mastication, and steer daily gains.}, number={3}, journal={CROP SCIENCE}, author={Burns, JC and Sollenberger, LE}, year={2002}, pages={873–881} }
 @article{archibeque_burns_huntington_2002, title={Nitrogen metabolism of beef steers fed endophyte-free tall fescue hay: Effects of ruminally protected methionine supplementation}, volume={80}, DOI={10.2527/2002.8051344x}, abstractNote={Level of nitrogen (N) intake and ruminally protected methionine supplementation were evaluated in eight Angus growing steers (initial BW 253+/-21 kg, final BW 296+/-21 kg) in a replicated 4+/-4 Latin square design. The steers were fed two endophyte-free tall fescue (Festuca arundinacea) hays that contained 2.2 (LO) or 2.8% (HI) of DM as N and were either supplemented or not with ruminally protected methionine (10 g metabolizable methionine/d). Diets were fed to provide adequate energy for 0.5 kg ADG and sufficient protein for maintenance (LO), or protein to support 0.5 kg ADG (HI). Following at least 14 d of adjustment, N balance was measured for 6 d. Isotopic urea was infused (15N15N-urea, 0.164 mmol urea N/h) via a jugular catheter for 56 h and urine was collected from 48 to 56 h to measure urea kinetics. Jugular blood was collected during the balance trial, and serum was analyzed for serum urea N (SUN). By design, daily N intake was greater (P < 0.05) for HI (112 g) than for LO (89 g). Compared with LO, steers when fed HI had greater (P < 0.05) daily DMI (4,217 vs 4,151 g), fecal N (34.4 vs 31.2 g), N digested (77.1 vs 57.7 g), urine N (48.3 vs 37.5 g), urine urea N excretion (34.6 vs 24.8 g), and N retained (29.8 vs 21.1 g). When fed HI steers also had higher (P < 0.05) urine urea N concentration (276 vs 219 mM), SUN (8.7 vs 6.7 mM), N digestibility (69.1 vs 64.9%), percentage of urinary N present as urea (71.5 vs 66.7%, P < 0.053), and rate of urea N production (59.6 vs 49.2 g/d) but lower (P < 0.05) percentage of urea N produced that was returned to the ornithine cycle (15.03 vs 19.2 1%) than when fed LO. Methionine supplementation decreased daily urine N (41.2 vs 44.6 g, P = 0.10) and increased both the amount of N retained daily (27.9 vs 23.7 g, P < 0.089) and the percentage of N digested that was retained (40.4 vs 34.6%, P < 0.094). In summary, supplemental methionine met a specific dietary limitation by increasing the amount of digested N that was retained by the steers.}, number={5}, journal={Journal of Animal Science}, author={Archibeque, S. L. and Burns, J. C. and Huntington, G. B.}, year={2002}, pages={1344–1351} }
 @article{fisher_mayland_burns_2002, title={Variation in ruminant preference for alfalfa hays cut at sunup and sundown}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.0231}, number={1}, journal={CROP SCIENCE}, author={Fisher, DS and Mayland, HF and Burns, JC}, year={2002}, pages={231–237} }
 @article{burns_fisher_mayland_2001, title={Preference by sheep and goats among hay of eight tall fescue cultivars}, volume={79}, DOI={10.2527/2001.791213x}, abstractNote={Grazing ruminants use both visual cues and taste in selecting their diet. Preference during grazing may not be the same when forage is dried for hay and cut into lengths prior to feeding in confinement. Eight cultivars of tall fescue (Festuca arundinacea Schreb.), previously evaluated for preference while grazed, were harvested three times over a period of 2 yr. The hays were air-dried, baled, and passed through a hydraulic bale processor prior to feeding. Five experiments were conducted. All three harvests were evaluated with sheep and the last two also with goats, using six animals each time. During an adaptation phase, hays were offered alone as meals. In the experimental phase, every possible pair of hays (28 pairs) was presented for a meal. Data were analyzed by multidimensional scaling and by traditional analyses. Preference was significant among cultivars in all experiments. Multidimensional scaling showed that selection was based on two criteria with two dimensions being significant. Sheep preferred KENHY followed by KENTUCKY 31 and STARGRAZER but preferenced against BARCEL. HIMAG, MO-96, and C1 were intermediate and MOZARK was variable. Goats were similar to sheep in preferring KENHY followed by STARGRAZER and selected against MOZARK and BARCEL. KENTUCKY 31, HIMAG, MO-96, and C1 were intermediate. In all five experiments, the general association was positive for available carbohydrate fractions and negative for fiber fractions that contribute to cell wall rigidity.}, number={1}, journal={Journal of Animal Science}, author={Burns, J. C. and Fisher, D. S. and Mayland, H. F.}, year={2001}, pages={213–224} }
 @article{archibeque_burns_huntington_2001, title={Urea flux in beef steers: Effects of forage species and nitrogen fertilization}, volume={79}, DOI={10.2527/2001.7971937x}, abstractNote={The effects of two forage species and N levels on urea kinetics and whole-body N metabolism were evaluated in eight Angus steers (initial BW 217+/-15 kg). In a replicated, 4 x 4 Latin square design, steers were fed gamagrass (Tripsacum dactyloides L.) or switchgrass (Panicum virgatum L.), each of which had 56.2 (LO) or 168.5 (HI) kg of N fertilization per hectare. Diets provided adequate energy for 0.5 kg ADG. Nitrogen balance and urea kinetics were measured from d 22 to 27 of each period. Urine samples collected during intravenous infusion of bis 15N urea were used to calculate production and recycling of urea N from relative abundance of urea isotopomers. Jugular blood serum was analyzed for serum urea N (SUN). Gamagrass differed from switchgrass (P < 0.05) in daily DMI (4,273 vs 4,185 g), N intake (72 vs 67 g), DM digestibility (61.0 vs 63.6%), fecal N (30.6 vs 28.3 g/d), urine urea N (10.5 vs 8.0 g/d), and percentage of urinary N present as urea N (53.5 vs 40.0%). After adjustment for differences in N intake, fecal N still tended to be greater (P < 0.09) for gamagrass than for switchgrass. The LO differed from the HI (P < 0.01) in daily N intake (63 vs 76 g), DM digestibility (61.3 vs 63.3%), urine N (13.6 vs 25.9 g/d), and N retained as a percentage of N digested (57.3 vs 43.5%). Compared to switchgrass, gamagrass had greater SUN, N digestibility, and N digested as N level increased (forage x N level interactions, P < 0.05). As N level increased, N retention increased from 19.5 to 23.5 g/d in gamagrass and decreased from 20.5 to 18.1 g/d in switchgrass (interaction, P < 0.07). The HI group was greater than the LO intake group (P < 0.03) in endogenous production of urea N (44.4 vs 34.0 g/d), gut entry rate of urea N (31.6 vs 28.2 g/d), and the amount of urea N that re-entered the ornithine cycle (9.4 vs 7.9 g/d). However, the percentage of urea N entering the gastrointestinal tract that was recycled was constant among treatments (29.1%), indicating that almost 70% of the urea N that entered the gastrointestinal tract was potentially available for anabolic purposes of the steers as a component of microbial products that were absorbed or excreted in the feces. In summary, N levels affected N metabolism of steers more when they were fed gamagrass than when they were fed switchgrass. Although the absolute amounts of N moving through the system changed with variations in intake, the proportions remained similar, with a greater efficiency of N use at low N intakes.}, number={7}, journal={Journal of Animal Science}, author={Archibeque, S. L. and Burns, J. C. and Huntington, G. B.}, year={2001}, pages={1937–1943} }
 @article{luginbuhl_pond_burns_fisher_2000, title={Intake and chewing behavior of steers consuming switchgrass preserved as hay or silage}, volume={78}, DOI={10.2527/2000.7871983x}, abstractNote={Effect of preservation method on intake and chewing behavior was examined using a first, late vegetative harvest (mid-June) of Kanlow switchgrass (Panicum virgatum L.). For silage (S), forage was harvested with a commercial field chopper (1.5 to 4 cm average chop length) and ensiled directly in silos 1.2 m in diameter and 3.6 m in height. For hay (H), forage was harvested with a flail-chopper (7 to 15 cm average chop length) and cured as hay in a drier at 77 degrees C. Diets of H and S were fed to six Hereford steers (338+/-5 kg) in a single crossover experiment. Chewing behavior was monitored for 4 d with a computerized system. At feeding, H was higher in DM and contained greater concentrations (DM basis) of NDF, CP, and hemicellulose, but lower concentrations of ADF and cellulose, and had lower in vitro DM disappearance values. Steers fed S had higher intakes of DM (P < .02) and NDF (P < .04) and consumed less water from the water supply (P < .01) than animals fed H. However, total amount of water (from water supply and feed) consumed per kilogram of DMI did not differ between diets. Crude protein intake was similar between diets. Preservation method had no effect on eating time, number of boli ruminated, bolus duration, and number of rumination chews per bolus. Steers fed S made fewer eating chews (P < .10) and ruminated for a longer time (P < .05) while making a greater number of rumination chews (P < .04) than steers fed H. Rumination intercycle time was slightly shorter in steers fed H (P < .05) than in steers fed S. When expressed per kilogram of NDF intake, steers fed S spent less time eating (P < .03) and made fewer eating chews (P < .02) than steers fed H; however, rumination time, number of rumination chews, and number of boli ruminated were not affected by preservation method. Steers fed S ingested feed at a greater rate (P < .03), excreted smaller fecal particles (P < .03), had meals of shorter duration (P < .06), spent less time eating during main meals (meals following feed distribution: P < .05), had more rumination periods (P < .01), and a shorter morning (P < .06) latency time (interval between end of main meal and onset of rumination) than steers fed H. These results indicate that preservation method with its concomitant differences in chop length affected forage chemical composition and voluntary intake, and that differences in chewing behavior occurred mostly during eating.}, number={7}, journal={Journal of Animal Science}, author={Luginbuhl, J. M. and Pond, K. R. and Burns, J. C. and Fisher, D. S.}, year={2000}, pages={1983–1989} }
 @article{merkel_pond_burns_fisher_2000, title={Rate and extent of dry matter digestibility in sacco of both oven- and freeze-dried Paraserianthes falcataria, Calliandra calothyrsus, and Gliricidia sepium}, volume={77}, number={1}, journal={Tropical Agriculture}, author={Merkel, R. C. and Pond, K. R. and Burns, J. C. and Fisher, D. S.}, year={2000}, pages={1–5} }
 @article{burns_chamblee_2000, title={Summer accumulation of tall fescue at low elevations in the Piedmont: I. Fall yield and nutritive value}, volume={92}, ISSN={["0002-1962"]}, DOI={10.1007/s100870050024}, number={2}, journal={AGRONOMY JOURNAL}, author={Burns, JC and Chamblee, DS}, year={2000}, pages={211–216} }
 @article{burns_chamblee_2000, title={Summer accumulation of tall fescue at low elevations in the humid Piedmont: II. Fall and winter changes in nutritive value}, volume={92}, ISSN={["1435-0645"]}, DOI={10.1007/s100870050025}, number={2}, journal={AGRONOMY JOURNAL}, author={Burns, JC and Chamblee, DS}, year={2000}, pages={217–224} }
 @article{merkel_pond_burns_fisher_1999, title={Intake, digestibility and nitrogen utilization of three tropical tree legumes I. As sole feeds compared to Asystasia intrusa and Brachiaria brizantha}, volume={82}, ISSN={["0377-8401"]}, DOI={10.1016/S0377-8401(99)00094-2}, abstractNote={The tropical tree legumes Paraserianthes falcataria, Gliricidia sepium, and Calliandra calothyrsus were fed to ram lambs to evaluate their potential as feeds. Dry matter intake, digestibility of dry matter, neutral detergent fiber and nitrogen, and digestible energy content were determined through a digestion study. The herbaceous dicot Asystasia intrusa was included as an underutilized source of nitrogen and Brachiaria brizantha was included as a standard tropical (C4) grass. Of the tree legumes, C. calothyrsus had the highest level of soluble phenolics (SPHE), averaging 38% of dry matter, and soluble proanthocyanidins (SPRO), averaging 13.7 absorbance units per gram (AU g−1) of dry matter. P. falcataria was intermediate, averaging 15% SPHE and 4.8 AU g−1 SPRO, with G. sepium the lowest, with 5% SPHE and 0.4 AU g−1 SPRO. Dry matter intake (percent of body weight) was lowest for C. calothyrsus-fed lambs, averaging 2.0%, compared with 3.2% for P. falcataria and 2.5% for G. sepium. Intakes were similar for A. intrusa and B. brizantha, averaging 2.6%. C. calothyrsus also had the lowest dry matter digestibility, averaging 55%, compared with 61% for P. falcataria and 63% for G. sepium, which were similar. Highest dry matter digestibility was obtained for A. intrusa, averaging 72%, and B. brizantha, averaging 65%. Forages had similar rank for neutral detergent fiber digestibility. Proanthocyanidins in the tree legumes may have bound with cell wall carbohydrates, resulting in a reduction in dry matter and NDF digestibilities. Digestible energy (kcal g−1) was highest for G. sepium, averaging 3.0, and ranged from 2.6 to 2.7 kcal g−1 for C. calothyrsus, P. falcataria, A. intrusa and B. brizantha. Fecal N was higher from the lambs fed tree legumes (average, 0.419 g kg−1 BW/day) compared with A. intrusa or B. brizantha (0.261 and 0.159 g kg−1 BW/day, respectively). This was attributed to higher fecal NDF-N, averaging 0.329 g kg−1 BW/day, from the tree legumes versus 0.162 g kg−1 BW/day for A. intrusa and 0.048 g kg−1 BW/day for B. brizantha. Consequently, apparent and true N digestibilities were lower for the tree legumes, averaging 61 and 69%, respectively, versus 73 and 84% for A. intrusa, and 76 and 93% for B. brizantha. Within the tree legumes, C. calothyrsus had lowest apparent and true N digestibility, averaging 51 and 57%, while P. falcataria and G. sepium had apparent and true N digestibilities averaging 67 and 76%. Proanthocyanidins and phenolic compounds in the three legumes, especially C. calothyrsus, were associated with reduced forage quality.}, number={1-2}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Merkel, RC and Pond, KR and Burns, JC and Fisher, DS}, year={1999}, month={Nov}, pages={91–106} }
 @article{merkel_pond_burns_fisher_1999, title={Intake, digestibility and nitrogen utilization of three tropical tree legumes II. As protein supplements}, volume={82}, ISSN={["0377-8401"]}, DOI={10.1016/S0377-8401(99)00095-4}, abstractNote={Calliandra calothyrsus, Paraserianthes falcataria and Gliricidia sepium leaves were supplemented at both 25 and 50% of dietary crude protein to a basal concentrate and fed to growing ram lambs. A control diet consisted of concentrate and the forage grass Brachiaria brizantha. Dry matter intakes and ADG of tree legume supplemented treatments were lower (P < 0.05) than control lambs, but increasing the amount of tree leaves fed did not result in further decreases in either dry matter intake or ADG. Dry matter digestibility was lower (P < 0.05) in both 25 and 50% dietary treatments compared with the control, while NDF digestibility was lower (P < 0.001) only in the 50% dietary treatments. Increasing the amount of leaves fed from all three tree species, led to decreased NDF digestibility. Fecal NDF-N was higher in tree-supplemented groups (P < 0.01) compared with control and increased (P < 0.05) with increasing amounts of tree leaves fed. Both apparent and true N digestibility were lower (P < 0.05) in C. calothyrsus, than in the other tree legume treatments. True N digestibility of 91% for the control was higher (P < 0.01) than the tree legume treatments supplemented at both 25 (range, 83–86%) and 50% dietary CP (range, 74–79%). Increasing the amount of tree leaves fed, regardless of tree species, decreased N digestibility in the diets. Higher fecal NDF-N and lower N digestibility in tree leaf supplemented lambs indicated that condensed tannins present in these tree species were binding protein and rendering it less available for digestion. Supplementation with C. calothyrsus, which had the highest levels of SPHE and SPRO, affected N utilization more negatively than did supplementation with either P. falcataria or G. sepium.}, number={1-2}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Merkel, RC and Pond, KR and Burns, JC and Fisher, DS}, year={1999}, month={Nov}, pages={107–120} }
 @article{fisher_mayland_burns_1999, title={Variation in ruminants' preference for tall fescue hays cut either at sundown or at sunup}, volume={77}, DOI={10.2527/1999.773762x}, abstractNote={Plants vary diurnally in concentrations of nonstructural carbohydrates. If ruminants prefer forages with higher total nonstructural carbohydrates (TNC), then the preference for hays harvested within the same 24-h period may vary. An established field of tall fescue (Festuca arundinacea Schreb.) was harvested six times in the vegetative stage. Harvests were paired such that each cutting at sundown (PM) was followed by a cutting the next morning at sunup (AM). We harvested in this manner three times, resulting in six hays. The hays were field-dried, baled, and passed through a hydraulic bale processor prior to feeding. Experiments were conducted with sheep, goats, and cattle, using six animals in each case. During an adaptation phase, hays were offered alone as meals. In the experimental phase, every possible pair of hays (15 pairs) was presented for a meal. Data were analyzed by multidimensional scaling and by traditional analyses. Multidimensional scaling indicated that selection was based on a single criterion. Preference for PM hays was greater than for AM hays (P < .01) in all experiments. Increased preference was associated with increased TNC (P < .01) and in vitro true DM disappearance (P < .01) and decreased fiber concentration (P < .01; NDF, ADF, cellulose, and ADL). Mowing hay late in the day was effective in increasing forage preference.}, number={3}, journal={Journal of Animal Science}, author={Fisher, D. S. and Mayland, H. F. and Burns, J. C.}, year={1999}, pages={762–768} }
 @book{belesky_burns_chamblee_daniel_ruiter_fisher_green_mochrie_mueller_pond_et al._1998, title={Carostan flaccidgrass: Establishment, adaption, production management, forage quality, and utilization}, publisher={Raleigh, NC: N.C. Agricultural Research Service, N.C. State University}, author={Belesky, D. P. and Burns, J.C. and Chamblee, Douglas S. and Daniel, Dorsey W. and Ruiter, J.M. and Fisher, D.S. and Green, J. T. and Mochrie, R. D. and Mueller, J. P. and Pond, K. R. and et al.}, year={1998} }
 @article{burns_chamblee_belesky_fisher_timothy_1998, title={Nitrogen and defoliation management: Effects on yield and nutritive value of flaccidgrass}, volume={90}, DOI={10.2134/agronj1998.00021962009000010016x}, abstractNote={Abstract}, number={1}, journal={Agronomy Journal}, author={Burns, J. C. and Chamblee, D. S. and Belesky, D. P. and Fisher, D. S. and Timothy, D. H.}, year={1998}, pages={85–92} }
 @article{edmisten_green_mueller_burns_1998, title={Winter annual small grain forage potential. I. Dry matter yield in relation to morphological characteristics of four small grain species at six growth stages}, volume={29}, ISSN={["1532-2416"]}, DOI={10.1080/00103629809369992}, abstractNote={Abstract Small grains offer a potential animal feed at a time when moisture is usually available in the Southeast. The four major winter annual small grains, barley, oats, rye, and wheat, have not been compared as potential feed sources in the same study in the past. These four small grains were harvested at six stages of growth: vegetative, boot, heading, milk, soft dough, and hard dough. Harvest dates, dry matter (DM) yield, DM yield of regrowth following initial harvest, DM concentration, and the proportions of leaf, stem and inflorescence were measured and used to evaluate the four species for silage production and grazing potential. Rye and barley reached boot prior to the suggested planting date for corn in the Piedmont of North Carolina and dry matter yields ranged from 4.72 to 6.71 Mg ha‐1 and were harvested. Barley reached milk, soft dough, and hard dough earlier than the other species and was equal to or higher than the other species in proportion of DM in leaf DM yield and total DM yield in 198...}, number={7-8}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Edmisten, KL and Green, JT and Mueller, JP and Burns, JC}, year={1998}, pages={867–879} }
 @article{edmisten_green_mueller_burns_1998, title={Winter annual small grain forage potential. II. Quantification of nutritive characteristics of four small grain species at six growth stages}, volume={29}, ISSN={["1532-2416"]}, DOI={10.1080/00103629809369993}, abstractNote={Abstract Four small grain species, barley, oat, rye, and wheat were harvested at six growth stages to investigate their nutritive quality as a possible replacement for corn silage. Crude protein (CP), in vitro dry matter disappearance (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF) and lignin contents were measured on fresh and ensiled samples. The IVDMD, an estimate of forage ruminant digestibility, of all species generally decreased from the vegetative (765–854 g kg‐1) through the milk stage (505–662 g kg‐1) and then remained unchanged or increased slightly through hard dough with the exception of oats which often decreased during later stages of growth. The IVDMD of rye was usually lower than the other species from the milk to hard dough stage. The IVDMD of barley was generally higher than the other species at the soft and hard dough stages. The NDF, ADF, and lignin fractions usually increased from the vegetative to milk stages and remained unchanged or increased slightly through the...}, number={7-8}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={Edmisten, KL and Green, JT and Mueller, JP and Burns, JC}, year={1998}, pages={881–899} }
 @article{burns_pond_fisher_luginbuhl_1997, title={Changes in forage quality, ingestive mastication, and digesta kinetics resulting from switchgrass maturity}, volume={75}, DOI={10.2527/1997.7551368x}, abstractNote={Five maturities of switchgrass hay harvested at 14-d intervals (vegetative through 20% heading) were fed to Hereford steers (297 kg) in a 5 x 5 Latin square. Relationships with switchgrass maturity were negative and quadratic (P < .05) for DMI and cubic (P < .05) for digestible DMI. Declines in apparent digestibilities of DM, ADF, and cellulose were cubic (P < .05), whereas these were quadratic (P < .05) for NDF, hemicellulose, and CP. Whole masticates from the least, mid, and most mature hays showed linear (P < .05) declines in DM concentration and IVDMD with increasing maturity, whereas NDF concentrations increased linearly (P < .05). Mean retention time of gastrointestinal DM increased linearly (P < .01) from 64 to 94 h from the least to the most mature hay, and the associated rate of passage declined linearly (P < .01) from 3.3 to 2.1%/h. Sieving of masticate DM showed a reduced proportion of large particles (> or = 2.8 mm) and an increased proportion of small particles (< or = .5 mm) with advancing forage maturity. More than 94% of the sieved fecal DM passed a 1.0-mm sieve, but particle sizes showed the same relationship with forage maturity as noted for masticate DM. This occurred despite the comminution from the rumination and digestive processes.}, number={5}, journal={Journal of Animal Science}, author={Burns, J. C. and Pond, K. R. and Fisher, D. S. and Luginbuhl, J.-M.}, year={1997}, pages={1368–1379} }
 @article{buntinx_pond_fisher_burns_1997, title={The utilization of multidimensional scaling to identify forage characteristics associated with preference in sheep}, volume={75}, DOI={10.2527/1997.7561641x}, abstractNote={Forage preference is difficult to assess but is likely an important factor in determining DM intake. In two experiments, six sheep (wethers, Exp. 1; ewes, Exp. 2) were used to obtain preference ratings on nine hays (Exp. 1) or nine fresh forages (Exp. 2). The statistical procedure of multidimensional scaling was used to develop orthogonal dimensions to account for the observed variation in preference for hays and fresh forages. This analysis produced three dimensions that accounted for 54% of the variation in mean 3-d preference for hays (Exp. 1). The three dimensions were subsequently associated by regression analysis with seven compositional variables. These were IVDMD and concentrations of monosaccharides, short-chain polysaccharides (SCP), and disaccharides in dimension 1(R2 = .99); acid detergent insoluble ash (ADIA) concentration, monosaccharide and SCP concentrations, and masticate NDF in dimension 2 (R2 = .99); and disaccharide and starch concentrations in dimension 3 (R2 = .65). Three dimensions accounting for 51% of the variation in fresh forage preference were found and related to four variables by regression analysis. These were disaccharide concentration and median particle size in dimension 1 (R2 = .76) and starch and monosaccharide + disaccharide concentrations in dimension 3 (R2 = .97). No physicochemical variables analyzed in this study were found to be significantly associated with the coordinates for the forages in dimension 2. Multidimensional scaling accounted for more than half the observed variation in animal preference and, in all but one case, these dimensions could be associated with physicochemical characteristics of the forages.}, number={6}, journal={Journal of Animal Science}, author={Buntinx, S. E. and Pond, K. R. and Fisher, D. S. and Burns, J. C.}, year={1997}, pages={1641–1650} }
 @article{burns_pond_fisher_1994, title={Measurement of forage intake}, ISBN={0891181199}, DOI={10.2134/1994.foragequality.c12}, abstractNote={An assay to determine the potential dry matter intake (DMI) of forage should reflect the animal's physiological status and diet selection without restrictions due to feeding level. Estimates of DMI of forage, other than at unrestricted levels of feeding, provide some integration of diet selectivity and lack of satiety. The maturation process in forage plants is the major contributor to the change in their nutritive value and, consequently, impacts DMI both within and among most forage species. Measuring the voluntary intake of animals is easiest to quantitate if the forage is brought to the animal and directly measured. Estimating the forage intake of free grazing animals is so difficult that all of the commonly used methods have limitations and consist of various compromises that may introduce error. Total fecal collection, along with an estimate of diet DM digestibility, has been used to estimate DMI.}, journal={National Conference on Forage Quality, Evaluation, and Utilization}, publisher={Madison, Wis. : American Society of Agronomy, Inc., Crop Science Society of America, Inc., and Soil Science Society of America, Inc}, author={Burns, J. C. and Pond, K. R. and Fisher, D. S.}, year={1994}, pages={494} }
 @article{burns_fisher_pond_1993, title={Ensiling characteristics and utilization of switchgrass preserved as silage}, volume={3}, DOI={10.1016/0925-5214(93)90015-u}, abstractNote={Switchgrass (Panicum virgatum L.) harvested at several maturities was readily ensiled when either directly cut and stored at a dry matter (DM) concentration of about 250 g kg−1 or wilted and stored at a DM concentration of about 350 g kg−1. Silage pH ranged from 4.6 to 5.1 for all treatments with acetic and lactic acids predominating. Acetic acid concentrations in the direct cut silage was double the concentrations in the wilted silage while lactic acid concentrations were similar. Forage at ensiling was high in cell walls (694 to 743 g kg−1) and low in crude protein (53 to 63 g kg−1). Silage was stable when either direct cut or wilted and well preserved when air was excluded. Forage artificially-dried (hay) or when ensiled (direct cut or wilted) did not alter DM intake (kg 100−1 kg body weight) which averaged 1.48 for the late boot stage and 1.41 when fully mature. Apparent digestion coefficients for DM and cell wall constituents of fully headed switchgrass showed no difference when preserved as hay or silage. Digestion coefficients from wilted silage were lower, however, than from direct cut silage for DM, crude protein, neutral detergent fiber, acid detergent fiber and cellulose. These results indicate that switchgrass can be preserved through fermentation with best results from immediate ensiling and subsequently utilized as silage in animal production systems.}, number={4}, journal={Postharvest Biology and Technology}, author={Burns, J. C. and Fisher, D. S. and Pond, K. R.}, year={1993}, pages={349} }
 @article{burns_pond_fisher_1991, title={Effects of grass species on growing steers: II. Dry matter intake and digesta kinetics}, volume={69}, DOI={10.2527/1991.6931199x}, abstractNote={Animal responses to treatments in grazing experiments frequently remain unexplained because of inadequate pasture and(or) animal measurements. This 2-yr study examined DMI, gastrointestinal tract fill of undigested DM (FILL), rate of digesta passage (ROP), and digesta mean retention time (MRT) for steers grazing tall fescue (Festuca arundinacea Schreb.), switchgrass (Panicum virgatum L.), flaccidgrass (Pennisetum flaccidum Griseb.), and bermudagrass (Cynodon dactylon [L.] Pers.). A randomized complete block design was used with two agronomic replicates. Comparisons in June (yr 1) among continuously grazed switchgrass (SG), flaccidgrass (FG), and bermudagrass (BG) or in May (yr 2) among tall fescue (TF), SG, and FG showed similar digesta kinetics, but different DMI (kg.d-1.100 kg BW-1), among these forages within each sampling. In the June evaluation, the DMI of SG and FG were similar (means = 3.09), DMI of bermudagrass (BG) was lowest (2.23), and fecal DM output (FO) was similar among forages. In the May evaluation, DMI by steers grazing SG (3.90) was higher than that by steers grazing FG (2.97); DMI of tall fescue (TF) was intermediate (3.41) but similar to DMI of FG. Differences in DMI were due to differences in diet in vitro DM disappearance (IVDMD) rather than to differences in digesta kinetics. In July (yr 2), the MRT was highest for BG (84 h) and similar for SG and FG (57 h). Steers grazing different forages exhibited similar ROP and FILL, but FO (kg.d-1.100 kg BW-1) among steers varied (.37 for steers fed BG; .74 for steers fed SG and FG).(ABSTRACT TRUNCATED AT 250 WORDS)}, number={3}, journal={Journal of Animal Science}, author={Burns, J. C. and Pond, K. R. and Fisher, D. S.}, year={1991}, pages={1199} }
 @article{burns_king_westerman_1990, title={LONG-TERM SWINE LAGOON EFFLUENT APPLICATIONS ON COASTAL BERMUDAGRASS .1. YIELD, QUALITY, AND ELEMENT REMOVAL}, volume={19}, ISSN={["0047-2425"]}, DOI={10.2134/jeq1990.00472425001900040019x}, abstractNote={Abstract}, number={4}, journal={JOURNAL OF ENVIRONMENTAL QUALITY}, author={BURNS, JC and KING, LD and WESTERMAN, PW}, year={1990}, pages={749–756} }
 @article{burns_rhykerd_noller_cummings_1974, title={INFLUENCE OF NITROGEN, PHOSPHORUS, AND POTASSIUM FERTILIZATION ON MINERAL CONCENTRATIONS IN MEDICAGO-SATIVA-L .1. SEASONAL-CHANGES}, volume={5}, ISSN={["1532-2416"]}, DOI={10.1080/00103627409366504}, abstractNote={Abstract An established stand of Ranger alfalfa was topdressed with equal rates, but different combinations, of N, P, and K. Five harvests were taken and the material analyzed for cation concentrations. Phosphorus application significantly increased P concentrations in alfalfa, but had little influence on concentration of other ions. Potassium applications showed striking effects by significantly increasing K levels of the forage while decreasing Ca, Mg, Cu, Zn, Al, and Mo levels. Significant differences occurred among harvest dates for 14 of the 16 cations analyzed. Seasonal trends were evident for SiO2, Zn, Al, Co, and Na. Applied N, P, and K and available soil P and K were associated with cation concentration of alfalfa and these interrelationships are discussed.}, number={4}, journal={COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS}, author={BURNS, JC and RHYKERD, CL and NOLLER, CH and CUMMINGS, KR}, year={1974}, pages={247–259} }
 @article{burns_goode_gross_linnerud_1973, title={COW AND CALF GAINS ON LADINO CLOVER-TALL FESCUE AND TALL FESCUE, GRAZED ALONE AND WITH COASTAL BERMUDAGRASS}, volume={65}, ISSN={["0002-1962"]}, DOI={10.2134/agronj1973.00021962006500060009x}, abstractNote={Abstract}, number={6}, journal={AGRONOMY JOURNAL}, author={BURNS, JC and GOODE, L and GROSS, HD and LINNERUD, AC}, year={1973}, pages={877–880} }