title: Effects of copper supplementation on feedlot performance, carcass characteristics, and rumen sulfur metabolism of growing cattle fed diets containing 60% dried distillers grains.
abstract: The effects of 3 supplemental Cu concentrations on feedlot performance, mineral absorption, carcass characteristics, and ruminal S metabolism of cattle fed diets containing 60% dried distillers grains with solubles (DDGS) were evaluated in 2 experiments. Experiment 1 was conducted with 84 Angus-cross yearling steers and heifers (initial BW = 238 ± 36 kg), which were blocked by gender and allocated to 12 pens. Supplemental dietary Cu (tribasic copper chloride) treatments were: 1) 0 mg Cu/kg diet DM, 2) 100 mg Cu/kg diet DM, 3) 200 mg Cu/kg diet DM. The remainder of the diet was DDGS (60%), grass hay (10%), pelleted soy hulls (15%), and a vitamin-mineral supplement (15%). Diets were offered ad libitum throughout the finishing phase (168 d). Three cattle from each pen (n = 36) were harvested on d 168 and carcass data and liver samples were collected. Copper supplementation did not affect ADG (P = 0.22). However, the nonsignificant trend for increased ADG and decreased DMI led to a linear increase (P = 0.02) feed efficiency (G:F = 0.167, 0.177, and 0.177 for 0, 100, and 200 mg Cu/kg diet DM, respectively). The apparent absorption of Cu decreased quadratically (P = 0.07) and the apparent absorption of Mn and Zn were decreased linearly (P = 0.03 and P = 0.05, respectively) with increased Cu supplementation. Cattle supplemented with 100 or 200 mg Cu/kg diet DM had greater liver Cu concentrations (P < 0.01) than cattle that were not supplemented with Cu. There were no treatment effects (P > 0.10) on HCW, LM area, USDA yield grade, backfat, or marbling score. Experiment 2 was conducted with 6 ruminally fistulated steers that were fed the same diets as in Exp 1 in a replicated 3 × 3 Latin Square design. Copper supplementation did not affect (P > 0.10) ruminal pH or liquid S(2-) concentrations in steers consuming 60% DDGS diets (total dietary S = 0.55%). From 3 to 9 h after feeding, H(2)S gas concentration was decreased in those cattle supplemented with 100 mg Cu/kg diet. Concentration of H(2)S gas did not differ among cattle supplemented with 0 or 200 mg Cu/kg diet DM on 60% DDGS diets. Supplemental Cu improved feed efficiency in cattle consuming diets containing 60% DDGS; however, effects of Cu on rumen S metabolism were minimal even when supplemented at twice the maximum tolerable limit for beef cattle (NRC, 2000).
authors.affiliation: Department of Animal Sciences, The Ohio State University, Wooster, OH 44691, USA.
authors.forename: T L
authors.initials: TL
authors.lastname: Felix
authors.forename: W P
authors.initials: WP
authors.lastname: Weiss
authors.forename: F L
authors.initials: FL
authors.lastname: Fluharty
authors.forename: S C
authors.initials: SC
authors.lastname: Loerch
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001823:Body Composition / Q000187:drug effects*; D002417:Cattle / Q000254:growth & development* / Q000378:metabolism*; D003300:Copper / Q000494:pharmacology*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004338:Drug Combinations; D002523:Edible Grain; D004958:Estradiol / Q000031:analogs & derivatives; D005260:Female; D006863:Hydrogen-Ion Concentration; D008297:Male; D011374:Progesterone; D012417:Rumen / Q000737:chemistry / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism*; D013739:Testosterone
chemical_list: D004338:Drug Combinations; C046521:estradiol benzoate, testosterone propionate drug combination; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D013455:Sulfur; D003300:Copper; C025370:estradiol benzoate, progesterone drug combination