@article{spears_kegley_mullis_2004, title={Bioavailability of copper from tribasic copper chloride and copper sulfate in growing cattle}, volume={116}, ISSN={["0377-8401"]}, DOI={10.1016/j.anifeedsci.2004.06.002}, abstractNote={Two experiments were conducted to determine the bioavailability of copper (Cu) from tribasic Cu chloride (Cu2(OH)3Cl) relative to Cu sulfate in growing steers. Experiment 1 compared tribasic Cu chloride to sulfate in terms of ability to maintain Cu status when supplemented to steers fed diets high in the Cu antagonists, molybdenum (Mo) and sulfur (S). Sixty Angus and Angus × Hereford steers (257 ± 2 kg body weight) were stratified by body weight and randomly assigned to treatments. Treatments consisted of 0, 5 or 10 mg supplemental Cu/kg diet DM from either Cu chloride or Cu sulfate. All diets were supplemented with 5 mg Mo/kg and 1.5 g S/kg. The control corn silage based diet analyzed 4.9 mg Cu/kg and 6.9 mg Mo/kg and was calculated to contain 3.0 g S/kg. Plasma and liver Cu concentrations and plasma ceruloplasmin activity decreased (P < 0.01) in all treatment groups during the 98-day study. Copper supplemented steers had higher (P < 0.01) plasma Cu, plasma ceruloplasmin, and liver Cu than controls at the end of the study. Steers supplemented with 10 mg Cu/kg had higher (P < 0.01) plasma Cu, plasma ceruloplasmin, and liver Cu than those receiving 5 mg Cu/kg diet. Bioavailability of Cu from Cu chloride, relative to Cu sulfate, was estimated from plasma Cu and ceruloplasmin on day 84 and liver Cu on day 98 using multiple linear regression and a slope ratio technique. Compared with Cu sulfate (1.00), relative bioavailability of Cu from tribasic Cu chloride was 1.32 (P < 0.08), 1.18 (P < 0.38) and 1.96 (P < 0.04) based on plasma Cu, plasma ceruloplasmin and liver Cu, respectively. In experiment 2, 43 Angus and Simmental steers (375 ± 7 kg BW) that had previously been depleted of Cu were used in a 21-day repletion study. Steers were randomly assigned within breed to treatment, and individually fed a corn silage based diet low in Mo (1.18 mg/kg). Treatments consisted of 0, 50 or 100 mg supplemental Cu/day from either Cu chloride or Cu sulfate. Plasma Cu, plasma ceruloplasmin and liver Cu increased (P < 0.01) in Cu supplemented, but not in control, steers. Plasma and liver Cu concentrations increased (P < 0.01) to a greater extent in steers receiving 100 mg Cu/day compared to those given 50 mg Cu/day. Tribasic Cu chloride and Cu sulfate were similar (P > 0.10) in their ability to increase Cu status in Cu depleted steers fed a diet low in Mo. Tribasic Cu chloride is more bioavailable than CuSO4 when added to diets high in the Cu antagonists Mo and S. When evaluated in Cu depleted steers fed diets low in Mo, the two Cu sources had a similar bioavailability.}, number={1-2}, journal={ANIMAL FEED SCIENCE AND TECHNOLOGY}, author={Spears, JW and Kegley, EB and Mullis, LA}, year={2004}, month={Sep}, pages={1–13} }
 @article{heugten_spears_kegley_ward_qureshi_2003, title={Effects of organic forms of zinc on growth performance, tissue zinc distribution, and immune response of weanling pigs}, volume={81}, DOI={10.2527/2003.8182063x}, abstractNote={This study was conducted to determine the effect of zinc level and source on growth performance, tissue Zn concentrations, intracellular distribution of Zn, and immune response in weanling pigs. Ninety-six 3-wk-old crossbred weanling pigs (BW = 6.45 +/- 0.17 kg) were assigned to one of six dietary treatments (four pigs per pen, four replicates per treatment) based on weight and litter origin. Treatments consisted of the following: 1) a corn-soybean meal-whey diet (1.2% lysine) with a basal level of 80 ppm of supplemental Zn from ZnSO4 (control; contained 104 ppm total Zn); 2) control + 80 ppm added Zn from ZnSO4; 3) control + 80 ppm added Zn from Zn methionine (ZnMet); 4) control + 80 ppm added Zn from Zn lysine (ZnLys); 5) control + 40 ppm added Zn from ZnMet and 40 ppm added Zn from ZnLys (ZnML); and 6) control + 160 ppm added Zn from ZnSO4. Zinc supplementation of the control diet had no effect on ADG or ADFI. Gain efficiency was less (P < 0.05) for pigs fed 80 ppm of Zn from ZnSO4 than for control pigs and pigs fed 160 ppm of Zn from ZnSO4. Organ weights, Zn concentration, and intracellular distribution of Zn in the liver, pancreas, and spleen were not affected (P = 0.12) by Zn level or source. Skin thickness response to phytohemagglutinin (PHA) was not affected (P = 0.53) by dietary treatment. Lymphocyte proliferation in response to PHA was greater (P < 0.05) in pigs fed ZnLys than in pigs fed the control diet or the ZnML diet; however, when pokeweed mitogen was used, lymphocyte proliferation was greatest (P < 0.05) in pigs fed the ZnMet diet than pigs fed the control, ZnLys, ZnML, or 160 ppm ZnSO4 diets. Antibody response to sheep red blood cells was not affected by dietary treatments. Supplementation of 80 ppm of Zn from ZnSO4 or ZnMet and 160 ppm of Zn from ZnSO4 decreased (P < 0.05) the antibody response to ovalbumin on d 7 compared with control pigs, but not on d 14. Phagocytic capability of peritoneal exudate cells was increased (P < 0.05) when 160 ppm of Zn from ZnSO4 was supplemented to the diet. The number of red blood cells ingested per phagocytic cell was increased (P < 0.05) in pigs fed the diet supplemented with a combination of ZnMet and ZnLys and the diet with 160 ppm of Zn from ZnSO4. Results suggest that the level of Zn recommended by NRC for weanling pigs was sufficient for optimal growth performance and immune responses, although macrophage function may be enhanced at greater levels of Zn. Source of Zn did not alter these measurements.}, number={8}, journal={Journal of Animal Science}, author={Heugten, Eric and Spears, J. W. and Kegley, E. B. and Ward, J. D. and Qureshi, M. A.}, year={2003}, pages={2063–2071} }
 @article{spears_kegley_2002, title={Effect of zinc source (zinc oxide vs zinc proteinate) and level on performance, carcass characteristics, and immune response of growing and finishing steers}, volume={80}, DOI={10.1093/ansci/80.10.2747}, abstractNote={Journal Article Effect of zinc source (zinc oxide vs zinc proteinate) and level on performance, carcass characteristics, and immune response of growing and finishing steers, Get access J. W. Spears, J. W. Spears 5Department of Animal Science and Interdepartmental Nutrition Program, North Carolina State University, Raleigh 27695-7621 3Correspondence: phone: 919/515-4008; fax: 919/515-4463; E-mail: Jerry_Spears@ncsu.edu. Search for other works by this author on: Oxford Academic PubMed Google Scholar E. B. Kegley E. B. Kegley 5Department of Animal Science and Interdepartmental Nutrition Program, North Carolina State University, Raleigh 27695-7621 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Animal Science, Volume 80, Issue 10, October 2002, Pages 2747–2752, https://doi.org/10.1093/ansci/80.10.2747 Published: 01 October 2002 Article history Received: 31 January 2002 Accepted: 30 May 2002 Published: 01 October 2002}, number={10}, journal={Journal of Animal Science}, author={Spears, J. W. and Kegley, E. B.}, year={2002}, pages={2747–2752} }
 @article{kegley_spears_flowers_schoenherr_2002, title={Iron methionine as a source of iron for the neonatal pig}, volume={22}, ISSN={["0271-5317"]}, DOI={10.1016/s0271-5317(02)00434-7}, abstractNote={Neonatal pigs (143) were used to determine if adequate iron (Fe) would be stored following a single oral dose of Fe methionine (FeMet) to prevent anemia through 21 d of age. Treatments consisted of: control (no Fe), 200 mg injectable Fe as gleptoferron within 12 h of birth (at birth), 100 or 200 mg Fe as FeMet orally at birth, or 200 mg Fe as FeMet or FeSO4 orally on d 3. Pigs given injectable Fe had higher hemoglobin concentrations than other treatments at 14 and 21 d. Utilization of Fe from FeMet was greatest when given at 3 d compared to at birth. Based on hemoglobin concentrations at 21 d, relative bioavailability of Fe from FeMet given on d 3 was 180% compared to FeSO4. Iron methionine given orally was a safe, effective source of Fe, but a single oral dose of FeMet was not equivalent to injectable Fe.}, number={10}, journal={NUTRITION RESEARCH}, author={Kegley, EB and Spears, JW and Flowers, WL and Schoenherr, WD}, year={2002}, month={Oct}, pages={1209–1217} }
 @article{kegley_spears_auman_2001, title={Dietary phosphorus and an inflammatory challenge affect performance and immune function of weanling pigs}, volume={79}, DOI={10.2527/2001.792413x}, abstractNote={Ninety-six 3-wk-old pigs (6.3+/-0.12 kg initial BW) were allotted to one of eight treatments based on BW and litter origin to determine the effect of dietary phosphorus and an inflammatory challenge on performance and immune function. Four corn-soybean meal-based treatment diets were formulated to contain 0.16, 0.24, 0.32, or 0.40% available P. Monocalcium-dicalcium phosphate was used as the supplemental P source. The Ca:available P ratio was maintained at 2:1. To challenge the pigs, half of the pigs in each dietary treatment were injected i.m. with E. coli lipopolysaccharide (200 microg/kg of BW) on d 7 and 14. This resulted in a 2 x 4 factorial arrangement of treatments. Average daily gain for the 35-d study was increased linearly (P < 0.01) by increasing supplemental P. Average daily gain and ADFI were decreased (P < 0.05) by lipopolysaccharide injection. Serum P concentrations increased linearly (P < 0.01) with increasing supplemental P. Antibody titers to the injection of sheep red blood cells and ovalbumin on d 21 decreased linearly (P < 0.10) by increasing supplemental P. In vitro blastogenic response of lymphocytes to phytohemagglutinin (PHA) on d 25 was increased linearly (P < 0.05) by increasing supplemental P. Blastogenic response of lymphocytes to pokeweed mitogen on d 25 was not affected. On d 31, skinfold thickness 6 h following an intradermal injection of PHA was increased quadratically (P < 0.07) by increasing supplemental P. There were no P x lipopolysaccharide interactions for any immune response measure. In conclusion, increasing supplemental P increased ADG and enhanced cell-mediated immune response but decreased humoral immune response.}, number={2}, journal={Journal of Animal Science}, author={Kegley, E. B. and Spears, J. W. and Auman, S. K.}, year={2001}, pages={413–419} }
 @article{kegley_spears_1999, title={Chromium and cattle nutrition}, volume={12}, ISSN={["0896-548X"]}, DOI={10.1002/(SICI)1520-670X(1999)12:2<141::AID-JTRA11>3.0.CO;2-H}, abstractNote={Until recently, practical diets fed to cattle were assumed to provide sufficient chromium to meet requirements. Recent research now suggests that in some situations practical diets may not contain adequate chromium to maximize certain biological processes in ruminants. Supplementation of chromium has increased blood glucose clearance rates following intravenous infusions of glucose and/or insulin in some studies with calves. However, one experiment with lactating cows indicated that supplemental chromium decreased sensitivity to insulin. Differences in responses may reflect the energy balance of the animal. Early in lactation, cows are in a negative energy balance, whereas growing calves are in a positive energy balance. Supplemental chromium has increased milk production in first lactation cows. Gain and feed efficiency have been increased by supplementation of chromium in some experiments, but not in others. Lipid metabolism also has been affected by supplemental chromium. Lower concentrations of blood ketone bodies have been observed in cows supplemented with chromium. Chromium supplementation has not altered backfat thickness or increased lean composition of beef carcasses. Several forms of supplemental chromium have been investigated in cattle diets, including chromium nicotinic acid complex, chromium tripicolinate, high chromium yeast, amino acid-chelated chromium, and chromium chloride. Responses have varied between sources in the few studies where different supplemental sources have been compared. Presently, no supplemental chromium sources are approved for addition to cattle diets. One problem is that little is known regarding the bioavailability of chromium in feeds commonly used in cattle diets. Further research is needed to determine when supplementation of chromium will impact cattle performance. J. Trace Elem. Exp. Med. 12:141–147, 1999. © 1999 Wiley-Liss, Inc.}, number={2}, journal={JOURNAL OF TRACE ELEMENTS IN EXPERIMENTAL MEDICINE}, author={Kegley, EB and Spears, JW}, year={1999}, pages={141–147} }
 @article{kegley_spears_brown_1997, title={Effect of shipping and chromium supplementation on performance, immune response, and disease resistance of steers}, volume={75}, DOI={10.2527/1997.7571956x}, abstractNote={Forty-eight Angus crossbred steers (263 +/- 2 kg initial BW) were blocked by weight and randomly assigned within weight group to treatment. Treatments consisted of control or .4 mg of supplemental Cr as Cr-nicotinic acid complex/kg of DM. Steers were fed diets containing 90% corn silage (DM basis) and 10% of a soybean meal-mineral-vitamin supplement. After 56 d on the dietary treatment, half of the steers in each treatment were transported 343 km and unloaded in an unfamiliar location. The next day, d 58, shipped steers were returned to the feedlot (50 km). On d 58 after shipped steers were returned to the feedlot, all steers were inoculated with infectious bovine rhinotracheitis virus (IBRV) intranasally. Average daily gain from d 0 to 80 was increased (P < .10) by supplemental Cr. There was a shipping x time interaction for serum cortisol concentrations. Shipping increased (P < .02) serum cortisol on d 58, but 7 d after transport there were no effects of shipping on serum cortisol. Transportation increased (P < .05) the ratio of neutrophils to lymphocytes. Supplemental Cr did not affect rectal temperature after the IBRV challenge or the antibody response to IBRV or porcine red blood cells. Immunoglobulin G antibody response to porcine red blood cells was decreased (P < .09) by shipping. Supplemental Cr as Cr-nicotinic acid improved ADG of growing steers, regardless of whether they had been stressed by shipping. Supplemental Cr did not affect any of the immune responses that were measured.}, number={7}, journal={Journal of Animal Science}, author={Kegley, E. B. and Spears, J. W. and Brown, T. T.}, year={1997}, pages={1956–1964} }
 @article{kegley_spears_eisemann_1997, title={Performance and glucose metabolism in calves fed a chromium-nicotinic acid complex or chromium chloride}, volume={80}, ISSN={["0022-0302"]}, DOI={10.3168/jds.S0022-0302(97)76107-1}, abstractNote={Twenty-four Holstein bull calves were fed a milk replacer diet to assess the effects of Cr on calf performance and metabolism of glucose. Treatments consisted of no supplemental Cr (control) or 0.4 mg/kg of dry matter of supplemental Cr from CrCl3 or from a Cr-nicotinic acid complex. Supplementation with the Crt-nicotinic acid complex increased the average daily gain and feed efficiency from d 28 to 42, but not over the entire 63-d performance phase. Calves that were fed diets supplemented with CrCl3 or the Cr-nicotinic acid complex had lower plasma glucose concentrations at 45 to 180 min after an i.v. infusion of insulin than did controls. Calves fed diets supplemented with the Cr-nicotinic acid complex also had lower plasma glucose concentrations from 90 to 180 min after insulin challenge than did calves that were fed diets supplemented with CrCl3. After an i.v. infusion of glucose, calves that were fed diets supplemented with CrCl3 had lower serum insulin concentrations at 10 to 25 min after challenge than did controls or calves that were fed diets supplemented with the Cr-nicotinic acid complex. However, the glucose clearance rate after glucose infusion was not affected by Cr supplementation. Chromium supplementation did not markedly affect the performance of calves, but the Cr-nicotinic acid complex and CrCl3 did intensify the response to insulin administered i.v.}, number={8}, journal={JOURNAL OF DAIRY SCIENCE}, author={Kegley, EB and Spears, JW and Eisemann, JH}, year={1997}, month={Aug}, pages={1744–1750} }
 @article{kegley_spears_brown_1996, title={Immune response and disease resistance of calves fed chromium nicotinic acid complex or chromium chloride}, volume={79}, ISSN={["0022-0302"]}, DOI={10.3168/jds.S0022-0302(96)76482-2}, abstractNote={Twenty-one Holstein bull calves (< 7 d of age at the initiation of the experiment) fed a milk replacer diet were used to assess the effects of supplemental Cr on immune response. Treatments consisted of milk replacer without supplemental Cr (control) or milk replacer with 0.4 ppm of supplemental Cr from CrCl3 or a Cr-nicotinic acid complex. On d 64, increases in skinfold thickness after an intradermal injection of phytohemagglutinin were measured to evaluate cell-mediated immune response. Calves supplemented with Cr-nicotinic acid complex had a greater response than did controls at 6, 12, 24, and 48 h after injection. Calves supplemented with CrCl3 had a greater response than did controls at 24 and 48 h after injection. In vitro blastogenic responses of lymphocytes to phytohemagglutinin or pokeweed mitogen and antibody response to porcine red blood cells were not affected by treatment. Following a disease challenge with an intranasal dose of infectious bovine rhinotracheitis on d 75, body temperature tended to be lower for calves supplemented with Cr-nicotinic acid complex than for control calves. Calves supplemented with either Cr source had lower serum cortisol concentrations at 5 d after challenge. Chromium supplementation enhanced cell-mediated immune function.}, number={7}, journal={JOURNAL OF DAIRY SCIENCE}, author={Kegley, EB and Spears, JW and Brown, TT}, year={1996}, month={Jul}, pages={1278–1283} }
 @article{kegley_spears_1995, title={Immune response and performance of sheep fed supplemental zinc as zinc oxide or zinc methionine}, volume={11}, number={3}, journal={Sheep & Goat Research Journal}, author={Kegley, E. B. and Spears, J. W.}, year={1995}, pages={127} }
 @article{kegley_spears_1995, title={Immune response, glucose metabolism, and performance of stressed feeder calves fed inorganic or organic chromium}, volume={73}, number={9}, journal={Journal of Animal Science}, author={Kegley, E. B. and Spears, J. W.}, year={1995}, pages={2721} }
 @article{kegley_spears_1994, title={BIOAVAILABILITY OF FEED-GRADE COPPER SOURCES (OXIDE, SULFATE, OR LYSINE) IN GROWING CATTLE}, volume={72}, ISSN={["1525-3163"]}, DOI={10.2527/1994.72102728x}, abstractNote={Plasma Cu concentrations and ceruloplasmin (a Cu metalloenzyme) activity were used to assess relative Cu bioavailability from different Cu sources for growing cattle. In Exp. 1, 18 calves (average BW 207 +/- 7.7 kg) that had been fed Cu-deficient diets since birth were randomly assigned to treatment. Treatments consisted of control (n = 3) or 30 mg/d of supplemental Cu (n = 5/treatment) from Cu oxide (CuO), Cu sulfate (CuSO4), or Cu lysine. Blood samples were obtained for plasma Cu and ceruloplasmin activity on d 0, 7, 14, and 21. Plasma Cu and ceruloplasmin activity were greater (P < .05) on d 7, 14, and 21 for calves supplemented with CuSO4 than for controls. Copper status of calves fed Cu lysine did not differ from that of calves fed CuSO4. Compared with d-0 values, plasma Cu concentrations by d 21 had increased by 95 and 98% in calves supplemented with CuSO4 and Cu lysine, respectively. Copper oxide supplementation did not increase Cu status above that observed in control calves. In Exp. 2, 36 calves (average BW 211 +/- 4.4 kg) were used to compare the relative bioavailability of Cu from CuO and CuSO4 when supplemented to corn silage-based diets high in the Cu antagonists iron (Fe) or molybdenum (Mo). Treatments consisted of no supplemental Cu or 8 mg of supplemental Cu/kg diet from either CuSO4 or CuO. Within each Cu treatment, diets were supplemented with 600 mg of Fe or 5 mg of Mo/kg diet. In calves fed 5 mg of Mo/kg, plasma Cu was lower (P < .05) in those fed no supplemental Cu or CuO compared with calves fed CuSO4 by d 91 and at subsequent sampling dates throughout the 154-d study. Plasma ceruloplasmin activity was decreased (P < .01) by Mo and was increased (P < .05) by CuSO4 compared with CuO. Based on plasma Cu and ceruloplasmin activity, CuSO4 and Cu lysine were similar in bioavailability, but CuO was essentially unavailable.}, number={10}, journal={JOURNAL OF ANIMAL SCIENCE}, author={KEGLEY, EB and SPEARS, JW}, year={1994}, month={Oct}, pages={2728–2734} }
 @article{kegley_spears_1994, title={EFFECT OF ZINC SUPPLEMENTATION ON PERFORMANCE AND ZINC-METABOLISM OF LAMBS FED FORAGE-BASED DIETS}, volume={123}, ISSN={["0021-8596"]}, DOI={10.1017/S002185960006857X}, abstractNote={Summary}, journal={JOURNAL OF AGRICULTURAL SCIENCE}, author={KEGLEY, EB and SPEARS, JW}, year={1994}, month={Oct}, pages={287–292} }
 @article{kegley_harvey_spears_1991, title={Effects of lysocellin and calcium level on mineral metabolism, performance and ruminal and plasma characteristics of beef steers}, volume={69}, number={2}, journal={Journal of Animal Science}, author={Kegley, E. B. and Harvey, R. W. and Spears, J. W.}, year={1991}, pages={782} }
 @article{kegley_harvey_spears_crickenberger_1990, title={The effects of lysocellin and varying calcium levels on performance and ruminal and plasma characteristics of growing beef steers fed corn silage}, volume={68}, number={2}, journal={Journal of Animal Science}, author={Kegley, E. B. and Harvey, R. W. and Spears, J. W. and Crickenberger, R. G.}, year={1990}, pages={483} }