@article{armstrong_cook_ward_williams_spears_2004, title={Effect of dietary copper source (cupric citrate and,cupric sulfate) and concentration on growth performance and fecal copper excretion in weanling pigs}, volume={82}, DOI={10.1093/ansci/82.4.1234}, number={4}, journal={Journal of Animal Science}, author={Armstrong, T. A. and Cook, D. R. and Ward, M. M. and Williams, C. M. and Spears, J. W.}, year={2004}, pages={1234–1240} }
 @article{creech_spears_flowers_hill_lloyd_armstrong_engle_2004, title={Effect of dietary trace mineral concentration and source (inorganic vs. chelated) on performance, mineral status, and fecal mineral excretion in pigs from weaning through finishing}, volume={82}, DOI={10.2527/2004.8272140x}, abstractNote={Two hundred and sixteen weanling gilts (6.65+/-0.08 kg) were used to determine the effects of decreasing supplemental concentrations of Zn, Cu, Fe, and Mn, and trace mineral source (inorganic vs. chelated) on growth performance, mineral status, and fecal mineral concentrations from weaning through development. The study was conducted over three trials with 72 pigs in each trial. Gilts were blocked by weight and randomly assigned to either 1) control, 2) reduced inorganic, or 3) reduced chelated trace minerals. The control diet was supplemented with 25, 150, 180, and 60 mg/kg of Cu, Zn, Fe, and Mn (in sulfate forms), respectively, during the nursery phase and 15, 100, 100, and 40 mg/kg of supplemental Cu, Zn, Fe, and Mn, respectively, during the growing and gilt-developer phases. Reduced inorganic and reduced chelated treatments were supplemented during all phases with 5, 25, 25, and 10 mg/kg of Cu, Zn, Fe, and Mn, respectively. The reduced chelated treatment supplied 50% of the supplemental Cu, Zn, Fe, and Mn in the form of metal proteinates, with the remainder from sulfate forms. Performance by control pigs did not differ from pigs fed the reduced trace mineral treatments during the nursery and grower-development periods. Gain:feed was lower (P < 0.05) for pigs fed the reduced inorganic compared with those fed the reduced chelated treatment during the nursery period. Trace mineral source did not affect performance during the growing or gilt-developer phase. Plasma Zn concentration and alkaline phosphatase activity were higher (P < 0.01) in control pigs than in those receiving reduced trace minerals during the nursery and growing phases. Plasma Cu concentration and ceruloplasmin activity were generally not affected by treatment. Hemoglobin concentrations were lower (P < 0.05) for the reduced inorganic compared with the reduced chelated treatment in the nursery phase. Fecal concentrations of Cu, Zn, and Mn were lower (P < 0.05) in pigs fed reduced trace minerals than in controls during all production phases. Fecal Zn concentration during the nursery and fecal Cu concentrations during the growing and gilt-developer phases were lower (P < 0.05) in pigs fed the reduced chelated compared with the reduced inorganic treatment. Results indicate that reducing the concentrations of Zn, Cu, Mn, and Fe typically supplemented to pig diets will greatly decrease fecal mineral excretion without negatively affecting pig performance from weaning through development.}, number={7}, journal={Journal of Animal Science}, author={Creech, B. L. and Spears, J. W. and Flowers, W. L. and Hill, G. M. and Lloyd, K. E. and Armstrong, T. A. and Engle, T. E.}, year={2004}, pages={2140–2147} }
 @article{armstrong_spears_2003, title={Effect of boron supplementation of pig diets on the production of tumor necrosis factor-alpha and interferon-gamma}, volume={81}, DOI={10.2527/2003.81102552x}, abstractNote={Two experiments were conducted to determine the effects of dietary B on the production of cytokines following an endotoxin challenge. In both experiments, pigs were obtained from litters generated from sows fed low-B (control) or B-supplemented (5 mg/ kg, as-fed basis) diets. In Exp. 1 and 2, 28 and 35 pigs, respectively (21 d old), remained with their littermates throughout a 49-d nursery phase and were fed either a control or B-supplemented diet. In Exp. 1, 12 pigs per treatment were moved to individual pens at the completion of the nursery phase and fed their respective experimental diet. On d 99 of the study, pigs were injected with 150 microg of phytohemagglutinin (PHA) to evaluate a local inflammatory response. Pigs receiving the B-supplemented diet had a decreased (P < 0.01) inflammatory response following PHA injection. Peripheral blood monocytes were isolated from six pigs per treatment on d 103 and cultured in the presence of lipopolysaccharide (LPS) to determine the effect of dietary B on tumor necrosis factor-alpha (TNF-alpha) production from monocytes. Isolated monocytes from pigs that received the B-supplemented diet had a numerically greater (P = 0.23) production of TNF-alpha. In Exp. 2, pigs were group housed with their littermates following the nursery phase for 43 d, after which 10 pigs per treatment were moved to individual pens. In Exp. 1 and 2, pigs were assigned randomly within dietary treatment to receive either an i.m. injection of saline or LPS on d 117 and d 109, respectively. The dose of LPS in Exp. 1 and 2 was 100 and 25 microg of LPS/kg of BW, respectively. In Exp. 1, serum TNF-alpha was increased (P < 0.01) at 2 h and tended to be increased (P < 0.11) at 6 and 24 h after injection by dietary B; however, only numerical trends existed for a B-induced increase in TNF-alpha in Exp. 2. Serum interferon-gamma (IFN-gamma) was increased (P < 0.01) at 6 h and tended to be increased (P < 0.08) at 24 h after injection in Exp. 1. In Exp. 2, dietary B also numerically increased IFN-alpha. These data indicate that dietary B supplementation increased the production of cytokines following a stress, which indicates a role of B in the immune system; however, these data do not explain the reduction in localized inflammation following an antigen challenge in pigs.}, number={10}, journal={Journal of Animal Science}, author={Armstrong, T. A. and Spears, J. W.}, year={2003}, pages={2552–2561} }
 @article{armstrong_flowers_spears_nielsen_2002, title={Long-term effects of boron supplementation on reproductive characteristics and bone mechanical properties in gilts}, volume={80}, DOI={10.2527/2002.801154x}, abstractNote={An experiment was conducted to determine long-term effects of dietary boron (B) on reproductive and bone characteristics in gilts. Weanling gilts (n = 50) were allotted to 10 pens based on weaning weight and litter origin. Pens were randomly assigned to receive one of two dietary treatments that consisted of a basal diet low in B (control) and the basal diet supplemented with 5 mg of B/kg diet as sodium borate. Gilts remained on their respective experimental diets throughout the nursery phase, growing-finishing phase, sexual maturity, breeding, gestation, and lactation. The day of first observed standing estrus was defined as puberty, and each pubertal gilt was bred via AI at the second observed standing estrus. Eight randomly selected gilts per treatment were slaughtered at d 35 of gestation for the assessment of embryonic and reproductive characteristics, bone characteristics, and tissue B concentrations. The remaining pregnant gilts (control, n = 11; 5 mg supplemental B/kg diet, n = 10) farrowed, and litter characteristics at farrowing and weaning were determined. Age at puberty was not affected (P = 0.72) by B, and neither were the number of corpora lutea on the ovaries (P = 0.44) or the total number of embryos (P = 0.95) at d 35 of gestation. Boron supplementation increased (P = 0.05) pig weaning weight and tended (P = 0.11) to increase pig birth weight; however, no other litter characteristics were affected (P > 0.12) by B. Extrinsic and intrinsic strength measures of bone were increased (P < 0.09) by B. Fat-free bone ash percentage and bone mineral concentrations were not affected (P > or = 0.19) by dietary B. Supplemental B increased (P < or = 0.06) the B concentrations of the muscle, liver, and reproductive tissues. Serum osteocalcin concentrations tended (P = 0.13) to be increased by dietary B, which may be related to increased bone turnover in B-supplemented gilts. Results indicate that B may have beneficial effects upon reproductive and bone characteristics.}, number={1}, journal={Journal of Animal Science}, author={Armstrong, T. A. and Flowers, W. L. and Spears, J. W. and Nielsen, F. H.}, year={2002}, pages={154–161} }
 @article{armstrong_spears_2001, title={Effect of dietary boron on growth performance, calcium and phosphorus metabolism, and bone mechanical properties in growing barrows}, volume={79}, DOI={10.2527/2001.79123120x}, abstractNote={An experiment was conducted to evaluate the effects of dietary boron (B) on growth performance, bone mechanical properties, and calcium (Ca) and phosphorus (P) metabolism in pigs. Thirty-six barrows were weaned at approximately 21 d of age and randomly assigned to receive one of three dietary treatments. Treatments consisted of 1) low-B basal diet (control), 2) basal + 5 mg B/kg diet, and 3) basal + 15 mg B/kg diet. Boron was supplemented as sodium borate. Barrows remained on their respective experimental diets throughout the nursery (35 d) and growing (30 d) phases of production. Blood samples were obtained from each barrow at the end of each phase. Following the 30-d growing period, eight barrows per treatment were transferred to stainless steel metabolism crates. Barrows had an adjustment period of 7 d, followed by a 7-d total collection of urine and feces. All barrows were fed at 90% of the previous ad libitum grower intake of the control animals during the adjustment and collection periods. At the end of the 7-d collection period, barrows were killed and femurs and fibulas were harvested for the assessment of bone mechanical properties. During the nursery phase, ADG and ADFI were increased (P < 0.05) by B supplementation. Boron did not affect (P = 0.34) feed efficiency during the nursery phase. During the growing phase, ADG and ADFI were increased (P < 0.05) by B supplementation. Boron did not affect (P = 0.97) feed efficiency during the growing phase. Boron did not affect (P = 0.44) bone ash percentage, but B supplementation increased (P < 0.05) bone ash P. Ultimate shear force of the fibula was increased (P < 0.05) in barrows supplemented with 15 mg B/kg diet compared to barrows fed diets supplemented with 5 mg B/kg diet. Apparent absorption and retention of Ca and P were not affected (P > 0.05) by dietary B. These data indicate that B supplementation to pigs can increase growth and bone strength without greatly affecting Ca and P metabolism.}, number={12}, journal={Journal of Animal Science}, author={Armstrong, T. A. and Spears, J. W.}, year={2001}, pages={3120–3127} }
 @article{armstrong_spears_engle_see_2001, title={Effect of pharmacological concentrations of dietary copper on lipid and cholesterol metabolism in pigs}, volume={21}, ISSN={["0271-5317"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-0034754358&partnerID=MN8TOARS}, DOI={10.1016/s0271-5317(01)00332-3}, abstractNote={An experiment was conducted to determine if pharmacological concentrations of copper (Cu) affect lipid and cholesterol metabolism in Cu-adequate pigs. Treatments consisted of: control (10 ppm Cu as cupric sulfate, CuSO4); control + 66 or 225 ppm Cu as CuSO4; control + 33, 66, or 100 ppm Cu as cupric citrate (CuCit). Pigs were fed their respective diets throughout the nursery (35 d) and growing-finishing (GF; 103 d) phases. Copper increased (P < .05) serum cholesterol during the nursery phase, but 100 ppm CuCit decreased (P < .05) serum cholesterol relative to the control on d 42 of the GF phase. Serum triglycerides were increased (P < .05) by 225 ppm CuSO4 relative to the control on d 42 of the GF phase. Percent lipid and cholesterol concentrations of the semitendinosus muscle were not affected by Cu. Lipid percentage of the longissimus muscle was decreased (P < .06) by 225 ppm CuSO4 compared to the control, but Cu did not affect cholesterol concentration or fatty acid profile. These results indicate that pharmacological concentrations of Cu have little effect on cholesterol and lipid metabolism in the Cu-adequate pig.}, number={9}, journal={NUTRITION RESEARCH}, author={Armstrong, TA and Spears, JW and Engle, TE and See, MT}, year={2001}, month={Sep}, pages={1299–1308} }
 @article{armstrong_spears_lloyd_2001, title={Inflammatory response, growth, and thyroid hormone concentrations are affected by long-term boron supplementationin gilts}, volume={79}, DOI={10.2527/2001.7961549x}, abstractNote={An experiment was conducted to determine the long-term effects of dietary boron (B) on growth performance, immune function, and plasma and serum characteristics in gilts. Fifty weanling gilts were allotted to 10 pens based on weaning weight and litter origin. Pens were randomly assigned to receive one of two dietary treatments. Treatments consisted of a basal diet low in B (control) and the basal diet supplemented with 5 mg B/kg diet as sodium borate. Gilts remained on their respective experimental diets and with their penmates throughout the nursery, growing, and finishing phases. The B concentration of the basal diet was 0.98, 2.1, and 2.2 mg/kg diet during the nursery, growing, and finishing phases, respectively. At the end of each production phase, animals were weighed and feed consumption was determined to assess growth performance variables. In addition, blood samples were obtained from three randomly selected gilts per pen at the completion of each phase. Boron had no affect (P > 0.58) on growth performance during the nursery phase, but gilts receiving supplemental B had increased (P < 0.05) ADG at the end of the finishing phase and over the entire growing-finishing period. Serum concentrations of triiodothyronine (T3) tended (P < 0.07) to be reduced by dietary B at the end of the nursery phase, but serum thyroxine (T4) was not affected (P = 0.46) by B. At the completion of the growing phase, supplemental B decreased (P < 0.05) the concentrations of T3 and T4 in the serum. In addition, serum concentrations of total cholesterol and the activity of alkaline phosphatase were increased (P < 0.05) by dietary B at the end of the growing phase. Serum concentrations of urea N tended (P < 0.09) to be increased by B at the end of the growing phase. Beginning at d 95 of the experimental period, measures of immune function were assessed in randomly selected gilts. Boron decreased (P < 0.05) the inflammatory response to an intradermal injection of phytohemagglutinin. Boron did not affect (P > 0.30) the blastogenic response of isolated lymphocytes to mitogen stimulation or the humoral immune response against a sheep red blood cell suspension. Results indicate that B may affect serum thyroid hormone concentrations, the inflammatory response, and growth in pigs.}, number={6}, journal={Journal of Animal Science}, author={Armstrong, T. A. and Spears, J. W. and Lloyd, K. E.}, year={2001}, pages={1549–1556} }
 @article{armstrong_spears_crenshaw_nielsen_2000, title={Boron supplementation of a semipurified diet for weanling pigs improves feed efficiency and bone strength characteristics and alters plasma lipid metabolites}, volume={130}, ISSN={["1541-6100"]}, DOI={10.1093/jn/130.10.2575}, abstractNote={Two experiments were conducted to determine effects of dietary boron (B) on performance, plasma minerals and metabolites, and bone characteristics in young pigs. In Experiment 1, 48 pigs (24 males, 24 females; 21 d old) were allotted to pens, which were randomly assigned to one of the following dietary treatments: 1) control (natural ingredient diet; 6.7 mg B/kg diet), 2) control + 5 mg B/kg diet and 3) control + 15 mg B/kg diet. Boron was supplemented as sodium borate. In Experiment 2, 48 pigs (24 males, 24 females; 21 d old) were assigned to the same treatments described in Experiment 1; however, the basal diet was a semipurified diet (0.98 mg B/kg diet). Diets were fed for 40 d; on d 40, blood samples were obtained for determination of plasma mineral and metabolite concentrations. Femurs were harvested from 8 pigs per treatment on d 40 for determination of mechanical properties, ash and lipid percentage. In Experiment 1, B did not affect performance, plasma minerals or metabolites or bone properties. In Experiment 2, B supplementation improved (P: < 0.05) the gain:feed ratio and increased plasma cholesterol and triglyceride concentrations. There was a treatment x sex interaction (P: < 0.05) in Experiment 2 for bone lipid to be lower and bending moment to be higher, with the response occurring in male pigs. Other dependent variables in Experiment 2 were not affected by treatment. In conclusion, B supplementation of a low B diet elicited responses of physiologic importance to pigs. However, B supplementation of a natural ingredient diet did not elicit a response.}, number={10}, journal={JOURNAL OF NUTRITION}, author={Armstrong, TA and Spears, JW and Crenshaw, TD and Nielsen, FH}, year={2000}, month={Oct}, pages={2575–2581} }
 @article{armstrong_spears_heugten_engle_wright_2000, title={Effect of copper source (cupric citrate vs cupric sulfate) and level on growth performance and copper metabolism in pigs}, volume={13}, ISSN={["1011-2367"]}, DOI={10.5713/ajas.2000.1154}, number={8}, journal={ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES}, author={Armstrong, TA and Spears, JW and Heugten, E and Engle, TE and Wright, CL}, year={2000}, month={Aug}, pages={1154–1161} }
 @article{engle_spears_armstrong_wright_odle_2000, title={Effects of dietary copper source and concentration on carcass characteristics and lipid and cholesterol metabolism in growing and finishing steers}, volume={78}, DOI={10.2527/2000.7841053x}, abstractNote={We conducted an experiment to determine the effects of dietary copper (Cu) source and level on carcass characteristics, longissimus muscle fatty acid composition, and serum and muscle cholesterol concentrations in steers. Sixty Angus and Angus x Hereford steers were stratified by weight and initial liver Cu concentration within a breed and randomly assigned to treatments. Treatments consisted of: 1) control (no supplemental Cu); 2) 20 mg Cu/kg DM from Cu sulfate (CuSO4); 3) 40 mg Cu/kg DM from CuSO4; 4) 20 mg Cu/kg DM from Cu citrate; 5) 20 mg Cu/kg DM from Cu proteinate; and 6) 20 mg Cu/kg DM from tribasic Cu chloride. A corn silage-soybean meal-based diet was fed for 56 d. Steers were then switched to a high-concentrate diet. Equal numbers (n = 5) of steers per treatment were slaughtered after receiving the finishing diets for either 101 or 121 d. Serum cholesterol was not affected by treatment during the growing phase but was decreased (P < .05) in steers supplemented with Cu by d 84 of the finishing period and remained lower (P < . 05) at subsequent sampling periods. Longissimus muscle cholesterol concentration tended to be reduced (P < .11) by Cu supplementation. Hot carcass weight and backfat were lower (P < .05) in animals receiving supplemental Cu. However, Cu-supplemented and control steers had similar marbling scores. Longissimus muscle polyunsaturated fatty acid concentrations (18:2 and 18:3) were increased (P < .07) and saturated fatty acid concentrations tended (P < . 11) to be reduced by Cu supplementation. These results indicate that as little as 20 mg of supplemental Cu/kg diet can reduce backfat and serum cholesterol and increase muscle polyunsaturated fatty acids in steers fed high-concentrate diets.}, number={4}, journal={Journal of Animal Science}, author={Engle, T. E. and Spears, J. W. and Armstrong, T. A. and Wright, C. L. and Odle, J.}, year={2000}, pages={1053–1059} }
 @article{armstrong_williams_spears_schiffman_2000, title={High dietary copper improves odor characteristics of swine waste.}, volume={78}, ISSN={0021-8812}, url={http://dx.doi.org/10.2527/2000.784859x}, DOI={10.2527/2000.784859x}, abstractNote={We conducted two experiments to determine the effects of dietary copper concentration and source on odor characteristics of swine waste. In both experiments, 192 weanling gilts and barrows were allotted to 24 pens. Pens were randomly assigned to one of six dietary treatments, consisting of control (10 ppm Cu as cupric sulfate, CuSO4), 66 or 225 ppm Cu as CuSO4, or 33, 66, or 100 ppm Cu as cupric citrate (Cucitrate). An antibiotic was included in the diets for Exp. 1, but not Exp. 2. On d 28, fecal samples were randomly obtained from one pig per pen and stored at -20 degrees C until preparation and evaluation by an odor panel. The odor panel consisted of 10 individuals, and each panelist evaluated the odor intensity, irritation intensity, and odor quality of the samples. In Exp. 1, the odor and irritation intensity of the feces were lower (P < .05) from animals consuming diets containing 225 ppm Cu as CuSO4 and 66 or 100 ppm Cu as Cu-citrate compared to the control. The odor quality of the waste from animals consuming diets containing 225 ppm Cu as CuSO4 and 66 or 100 ppm Cu as Cu-citrate was improved (P < .05) compared to the 33 ppm Cu treatment. In Exp. 2, the odor intensity of the feces of pigs receiving diets supplemented with all concentrations of Cu-citrate was lower (P < .05) than that of feces from the control animals. Irritation intensity of the feces was not affected by treatment. Odor quality of waste of pigs supplemented with 225 ppm Cu from CuSO4 and all concentrations of Cu-citrate was improved (P < .05) compared to that of waste of the control pigs. Two gilts and two barrows from each nursery pen in Exp. 1 were continued through the growing-finishing phase on their respective experimental diets. The growing-finishing phase lasted 103 d, and fecal samples were randomly obtained from one pig per pen at the completion of the phase. During the growing-finishing phase, the odor intensity and the irritation intensity of the feces were lower (P < .05) from pigs supplemented with 66 and 225 ppm Cu as CuSO4 and 66 and 100 ppm Cu from Cu-citrate than from the control pigs. The odor quality of the waste was improved (P < .05) in all animals receiving supplemental Cu. These data indicate an improvement in odor characteristics of swine waste with the supplementation of Cu. In addition, lower concentrations of an organic nonsulfate Cu source resulted in similar odor characteristics of swine waste as 225 ppm CuSO4.}, number={4}, journal={Journal of Animal Science}, publisher={Oxford University Press (OUP)}, author={Armstrong, T A and Williams, C M and Spears, J W and Schiffman, S S}, year={2000}, pages={859} }
 @article{armstrong_flowers_britt_1999, title={Control of the weaning-to-estrus interval in sows using gonadotropins and prostaglandins during lactation}, volume={77}, DOI={10.2527/1999.7792533x}, abstractNote={Two experiments were conducted to examine the effectiveness of various strategies using gonadotropins to induce ovulation during lactation as a means of controlling the weaning-to-estrus interval in sows. The objective of Exp. 1 was to examine the efficacy of various gonadotropin regimens for induction of ovulation during lactation. Primiparous (n = 60) and multiparous (n = 83) crossbred sows were assigned, before farrowing, to one of four treatments: no injection (control); 1,000 IU hCG on d 0 (hCG-0; d 0 = day of farrowing); P.G. 600 + 1,000 IU hCG 4 and 7 d after farrowing, respectively (hCG-7); or P.G. 600 + 1,000 IU hCG 11 and 14 d after farrowing, respectively (hCG-14). Sows were weaned on 18 +/- 2 d after farrowing and monitored daily for estrus via exposure to mature boars. The criterion for determining the induction of ovulation was a sustained increase in serum progesterone concentrations above 4.0 ng/mL. The most consistent response to exogenous gonadotropins was on d 0, with an 80% response in primiparous sows (12/15) and a 71% response in multiparous sows (15/21). Weaning-to-estrus intervals for multiparous sows were longer (P = .05) for hCG-14 and hCG-7 than for control and hCG-0 sows. Weaning-to-estrus intervals for primiparous sows were longer (P = .05) for the hCG-14 than for the hCG-0 treatment. The objective of Exp. 2 was to ascertain the effects of postpartum treatment with hCG (1,000 IU) on d 0 and PGF2alpha (10 mg) at d 14 on the weaning-to-estrus interval in multiparous sows weaned at d 14 after birth. Before farrowing, sows (n = 60) were randomly assigned to one of four treatments: positive control, weaning at d 21; negative control, weaning at d 14; hCG within 24 h after farrowing, weaning at d 14; or hCG within 24 h after farrowing and PGF2alpha at weaning, weaning at d 14. Weaning-to-estrus intervals were longer (P = .05) in sows receiving PGF2alpha than in the other treatments. Results indicate that it is possible to induce ovulation immediately after farrowing, using a single injection of hCG, and this strategy can be used to uncouple weaning from the resumption of reproductive activity. However, the administration of PGF2alpha at 14 d after farrowing did not consistently cause regression of the induced corpora lutea.}, number={9}, journal={Journal of Animal Science}, author={Armstrong, T. A. and Flowers, W. L. and Britt, Jack}, year={1999}, pages={2533–2539} }