To investigate effects of inorganic or complexed trace mineral source (zinc, copper, manganese, and cobalt) on receiving period performance and morbidity, crossbred beef heifer calves (n = 287) arriving on 3 delivery dates were used in a 42-day receiving trial. Heifers were processed after arrival, stratified by d -1 body weights (BW) and allocated randomly to 8 pens (11 to 13 heifers/pen, 24 pens total). Within truckload, pens were assigned randomly to dietary treatment (n = 12 pens/treatment). Heifers were housed on 0.42-ha grass paddocks, provided ad libitum bermudagrass hay and provided dietary treatments in grain supplements fed daily. Treatments consisted of supplemental zinc (360 mg/d), copper (125 mg/d), manganese (200 mg/d), and cobalt (12 mg/d) from complexed (Zinpro® Availa® 4, Zinpro Corp. Eden Prairie, MN) or inorganic sources (sulfates). Heifers were observed daily for clinical bovine respiratory disease (BRD). If presenting BRD symptoms and rectal temperature ≥ 40°C, heifers were deemed morbid and treated with antibiotics. Six heifers/pen were bled to determine serum haptoglobin concentrations on days 0, 14 and 28. Liver biopsies were taken on d 5 ± 2 and 43 ± 1 from 3 calves selected randomly from each pen for mineral status comparisons. Statistical analyses were performed using MIXED, GLIMMIX, and repeated measures procedures of SAS 9.4 with truckload as a random effect and pen within truckload specified as subject. There tended to be a treatment by day interaction for BW (P = 0.07). Heifer BW did not differ on day 0 (P = 0.82) and day 14 (P = 0.36), but heifers fed complexed trace minerals had greater BW on day 28 (P = 0.04) and day 42 (P = 0.05). Overall average daily gains were greater for heifers fed complexed trace minerals (P = 0.05; 0.78 vs. 0.70 kg, SE = 0.03). Heifers supplemented with inorganic trace minerals had greater BRD incidence (P = 0.03; 58 vs. 46%, SE = 3.6). Haptoglobin concentrations decreased throughout the trial (P < 0.001), and heifers fed complexed trace minerals tended to have a decrease in haptoglobin concentrations (P = 0.07). The source of trace mineral supplementation had no effect (P ≥ 0.20) on liver mineral concentrations and there were no treatment × day interactions (P ≥ 0.35). In conclusion, supplementing diets for the first 42 days after arrival with complexed trace mineral sources improved heifer performance as compared to heifers supplemented with inorganic trace minerals.

中文翻译：

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在肉牛接收期间作为复合或无机来源补充微量矿物质

为了研究无机或复合微量矿物质源（锌、铜、锰和钴）对接收期性能和发病率的影响，在 3 个分娩日期到达的杂交小母牛犊 (n = 287) 被用于为期 42 天的接收试验。小母牛到达后进行处理，按 d -1 体重 (BW) 分层，并随机分配到 8 个栏（11 至 13 头小母牛/栏，总共 24 栏）。在卡车装载量内，猪栏被随机分配进行饮食治疗（n = 12 猪栏/治疗）。小母牛圈养在 0.42 公顷的草场上，随意提供狗牙根干草，并每天喂食谷物补充剂进行饮食治疗。治疗包括补充来自络合剂（Zinpro® Availa® 4，Zinpro Corp. Eden Prairie）的锌（360 毫克/天）、铜（125 毫克/天）、锰（200 毫克/天）和钴（12 毫克/天） ，MN）或无机来源（硫酸盐）。每天观察小母牛的临床牛呼吸道疾病（BRD）情况。如果出现 BRD 症状且直肠温度≥ 40°C，则小母牛被视为患病并接受抗生素治疗。在第 0、14 和 28 天，对 6 头小母牛/栏进行抽血以确定血清触珠蛋白浓度。在第 5 ± 2 和 43 ± 1 天，从每个栏随机选择 3 头小牛进行肝脏活检，以进行矿物质状态比较。使用 SAS 9.4 的 MIXED、GLIMMIX 和重复测量程序进行统计分析，其中卡车装载量作为随机效应，卡车装载量内的笔指定为受试者。BW 往往存在日间相互作用的治疗（P = 0.07）。小母牛体重在第 0 天 (P = 0.82) 和第 14 天 (P = 0.36) 没有差异，但饲喂复合微量矿物质的小母牛在第 28 天 (P = 0.04) 和第 42 天 (P = 0.05) 的体重更大。饲喂复合微量矿物质的小母牛的总体平均日增重更高（P = 0.05；0.78 vs. 0.70 kg，SE = 0.03）。补充无机微量矿物质的小母牛的 BRD 发生率较高（P = 0.03；58% vs. 46%，SE = 3.6）。在整个试验过程中，触珠蛋白浓度下降（P < 0.001），饲喂复合微量矿物质的小母牛的触珠蛋白浓度往往会降低（P = 0.07）。微量矿物质补充来源对肝脏矿物质浓度没有影响（P ≥ 0.20），并且不存在治疗×天数相互作用（P ≥ 0.35）。总之，与补充无机微量矿物质的小母牛相比，在抵达后前 42 天的日粮中添加复合微量矿物质源可改善小母牛的生产性能。