@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{mullis_spears_mccraw_2003, title={Effects of breed (Angus vs Simmental) and copper and zinc source on mineral status of steers fed high dietary iron}, volume={81}, DOI={10.2527/2003.811318x}, abstractNote={Forty-four Angus (n = 24) and Simmental (n = 20) steers, averaging 301 kg initially, were used to determine the effects of breed and Cu and Zn source (SO4 or proteinate (Prot) form) on Cu and Zn status of steers fed high dietary iron (Fe). Steers were stratified by weight within breed and randomly assigned to treatments. Treatments consisted of: 1) CuSO4 + ZnSO4 ,2) CuSO4 + ZnProt, 3) CuProt + ZnSO4, and 4) CuProt + ZnProt. Copper and Zn sources were added to provide 5 mg Cu and 25 mg supplemental Zn/kg DM. All steers were individually fed a corn silage-based diet supplemented with 1,000 mg Fe (from FeSO4)/kg DM. Liver biopsy samples were obtained at the beginning and end of the 149-d study. Serum samples were collected initially and at 28-d intervals for determination of ceruloplasmin activity and Zn and Cu concentrations. Copper and Zn source did not affect performance, serum or liver Cu and Zn concentrations, or ceruloplasmin activity. Copper status decreased (P < 0.01) in all steers with time, and increasing the level of supplemental Cu from 5 to 10 mg/kg DM on d 84 did not prevent further drops in serum Cu and ceruloplasmin. Simmental steers had lower (P < 0.05) serum and liver Cu concentrations, and serum ceruloplasmin activity throughout the study. These results indicate that neither CuSO4 nor CuProt were effective at the supplemental concentrations evaluated in alleviating the adverse effect of high Fe on Cu status. Simmental steers had lower Cu status than Angus, suggesting a higher Cu requirement.}, number={1}, journal={Journal of Animal Science}, author={Mullis, L. A. and Spears, J. W. and McCraw, R. L.}, year={2003}, pages={318–322} }
 @article{mullis_spears_mccraw_2003, title={Estimated copper requirements of Angus and Simmental heifers}, volume={81}, DOI={10.2527/2003.814865x}, abstractNote={In Exp. 1, Simmental (n = 21) and Angus (n = 21) heifers, approximately 9 mo of age, were used in a 160-d study to determine the effect of dietary Cu on growth and Cu status. Two- or three-yr-old first-calf heifers (21 Angus and 21 Simmental) entering into their last trimester of pregnancy were used in Exp. 2 to estimate Cu requirements of the two breeds during gestation and early lactation. Treatments in both studies consisted of 0 (control), 7, or 14 mg of supplemental Cu (as CuSO4)/kg of DM. The control corn silage-based diets contained 6.4 and 4.4 mg of Cu/kg of DM in Exp. 1 and 2, respectively, and 1.2 mg of Mo/kg. Dietary Cu did not affect performance in either breed in Exp. 1. Copper supplementation generally did not affect plasma Cu concentrations in Angus heifers, but increased (P < 0.05) plasma Cu in Simmental heifers from d 37 until the end of Exp. 1. Final liver Cu concentrations were lower (P < 0.05) than initial concentrations in control Angus and Simmental heifers; however, liver Cu increased (P < 0.01) in Cu-supplemented heifers. In Exp. 2, Cu supplementation of the control diet increased (P < 0.05) plasma Cu during gestation and greatly increased (P < 0.01) liver Cu in both breeds. Calves born to cows not supplemented with Cu also had lower plasma Cu concentrations than Cu-supplemented calves by 73 d of age. In both studies, control Simmental heifers had lower (P < 0.05) plasma Cu concentrations than Angus on most sampling dates. When Cu was supplemented at 7 or 14 mg/kg of DM,few differences in plasma Cu concentrations were observed between breeds. Results suggest that Angus heifers have a lower minimal Cu requirement than Simmental. Based on liver Cu, the control diets containing 4.4 or 6.4 mg of Cu/kg of DM did not meet the Cu requirement of either breed during gestation and lactation or growth. Addition of 7 mg of Cu/kg of DM to the control diets met Cu requirements of both breeds.}, number={4}, journal={Journal of Animal Science}, author={Mullis, L. A. and Spears, J. W. and McCraw, R. L.}, year={2003}, pages={865–873} }