@article{chavez_siciliano_huntington_2014, title={Intake estimation of horses grazing tall fescue (Lolium arundinaceum) or fed tall fescue hay}, volume={92}, ISSN={["1525-3163"]}, DOI={10.2527/jas.2013-7119}, abstractNote={Six mature geldings of light horse breeds (557 ± 37 kg) were randomly assigned to a nontoxic endophyte-infected tall fescue hay (n = 3) or pasture treatment (n = 3) in a crossover design with 14-d periods to estimate DMI with alkane markers and to compare DMI of hay and pasture. When fed pasture, horses were housed in stalls from 0700 to 1300 h daily with access to water and then grazed pasture as a group in a single 0.4 ha pasture from 1300 to 0700 h. When fed hay, horses were maintained individually in stalls and given access to hay ad libitum from 1300 to 0700 h. All horses were individually fed 225 g oats twice daily treated with hexatriacontane (C36; external marker) and fecal samples were collected at 0700 and 1900 h on d 10 to 14. Fecal samples were mixed, dried, subsampled, and analyzed for tritriacontane (C33) and hentriacontane (C31) as internal markers and C36 as the external marker using gas chromatography. Estimated hay DMI using either C33 (1.75 kg/100 kg BW) or C31 (1.74 kg/100 kg BW) as internal alkane marker did not differ (P = 0.55) from measured hay DMI (1.70 kg/100 kg BW). Pasture DMI and DM digestibility (DMD) estimated with C31 (2.24 kg/100 kg BW and 53.1 g/100 g DMI) or with C33 (2.34 kg/100 kg BW and 56.2 g/100 g DMI) was greater (P = 0.05) than hay DMI and DMD (1.74 kg/100 kg BW and 44.5 g/100 g DMI). Intake estimated with C33 or C31 did not differ (P = 0.35) during hay or pasture. In conclusion, alkanes can be used to estimate pasture or hay DMI and DMD, and pasture intake exceeded hay intake when offered ad libitum.}, number={5}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Chavez, S. J. and Siciliano, P. D. and Huntington, G. B.}, year={2014}, month={May}, pages={2304–2308} }
 @article{chavez_huntington_2013, title={Intake in cattle of a ground switchgrass and alfalfa hay mixture blended with various levels of sucrose or citric acid}, volume={184}, ISSN={["0377-8401"]}, DOI={10.1016/j.anifeedsci.2013.05.015}, abstractNote={Abstract Palatability of feed affects voluntary intake. The objectives were to evaluate preference by bovine for sweet (sucrose) or sour (citric acid) blended with a mixture of ground switchgrass (42 g crude protein/kg dry matter) and alfalfa hay (176 g crude protein/kg dry matter). Flavors were dissolved in 50 mL deionized water per kg of hay for blending. In Experiment 1, sucrose hay (S100) had 100 g sucrose added per kg hay. Citric acid hay (CA50) had 50 g citric acid added per kg hay. Control hay (CON) had 50 mL deionized water added per kg hay. In Experiment 2, treatments were CON, sucrose added at 25 g per kg hay (S25), S100, 150 g per kg hay (S150). Citric acid added at 25 g per kg hay (CA25), and CA50. Hays were mixed in a horizontal mixer 3 d prior to each experimental period. Twelve beef cattle (initial BW = 283 ± 25 kg) were housed under a roof on expanded metal flooring with access to six feed locations designated I through VI, west to east. Cattle consumed 1 kg/day of supplement (corn, soybean hulls, and trace mineralized salt) that was fed daily, after hay orts were removed and weighed at 0800. Cattle were offered treatment hay equal to 6 g per kg BW at each feed slot and treatments were randomly assigned to two of the six locations at 0830. Cattle were given a 14-d adaptation to CON followed by a 7-d offer of treatments. In Experiment 1, cattle preferred S100 (3.42 ± 0.04 kg/d) over CON (2.8 ± 0.04 kg/d, P}, number={1-4}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Chavez, Stephen J. and Huntington, Gerald B.}, year={2013}, month={Aug}, pages={33–37} }
 @article{chavez_huntington_burns_2011, title={Use of plant hydrocarbons as markers to estimate voluntary intake and digestibility in beef steers}, volume={139}, ISSN={["1871-1413"]}, DOI={10.1016/j.livsci.2011.01.012}, abstractNote={Calculating dry matter intake of grazing herbivores has been an issue in determining factors such as efficiency and digestibility of forages. Two experiments were conducted using alkanes to validate analytical methods with oven-dried and freeze-dried samples, compare and contrast measured and estimated intake, and to measure digestibility using a controlled-release capsule (CRC) or supplement. In the first trial, 7 beef steers consuming either alfalfa or switchgrass hay received either a CRC or supplement in a random crossover design. Each period lasted 20 days with fecal grab samples taken over the last 10 days and total fecal collection the last 5 days. In the second trial, 12 beef cattle were fed a blended switchgrass and alfalfa hay and fed a once-daily alkane supplement. Fecal grab samples were collected the last 5 days over the 14-day experiment. In the first experiment, steers fed switchgrass hay ate less and digested a smaller proportion of total diet (P < 0.02) than steers fed alfalfa. There was no difference (P < 0.35) between estimated intake and measured intake. Fecal concentrations of alkanes were not affected (P < 0.13) by drying method and no difference (P < 0.40) was seen between fecal grab samples and total fecal collection. Either dotriacontane (C32) or hexatriacontane (C36) can be used for estimating DMD. In the second experiment, there was no difference between measured and estimated intake (P < 0.35). There was no day effect between fecal concentrations and estimated intake. There was no difference (P < 0.65) between fecal alkane concentrations when duplicate samples were analyzed. Alkanes can be used to estimate intake in cattle. Fecal grab samples are sufficient to reduce labor and result in adequate estimated intake and daily feeding of alkanes can be used to replace the CRC.}, number={3}, journal={LIVESTOCK SCIENCE}, author={Chavez, S. J. and Huntington, G. B. and Burns, J. S.}, year={2011}, month={Aug}, pages={245–251} }