Supplemental trace minerals (zinc, copper, manganese, and cobalt) as Availa-4 or inorganic sources for shipping-stressed beef cattle 1

Male beef calves (n = 288, average BW 238 ± 1.1 kg) were obtained from sale barns. Within each set (n = 3), calves were allocated randomly within 4 weight blocks to pen (2 pens/block; 11 to 13 calves/pen). Pens within block were assigned randomly to treatment. During the 42-d backgrounding period, calves were on 0.42-ha paddocks, had ad libitum access to bermudagrass hay, and were fed corn-soybean meal supplements that served as the carrier for treatments. Treatments consisted of supplemental Zn (360 mg/d), Cu (125 mg/d), Mn (200 mg/d), and Co (12 mg/d) from inorganic (zinc sulfate, manganese sulfate, copper sulfate, and cobalt carbonate) or organic (zinc amino acid complex, manganese amino acid complex, copper amino acid complex, and cobalt glucoheptonate; Availa-4, Zinpro Corp., Eden Prairie, MN) sources. Calves supplemented with organic trace mineral sources had a greater final weight (271 vs. 267 kg for organic and inorganic, respectively; P = 0.04) and ADG (0.77 vs. 0.66 kg/d for organic and inorganic, respectively; P = 0.04) than calves supplemented with isolevels of trace minerals from inorganic sources. Supplementation with organic trace minerals tended (P = 0.09) to reduce the percentage of calves that received a second antibiotic treatment. When calves that had initial antibodies to infectious bovine rhinotracheitis virus (IBRV) were removed, the naïve calves supplemented with inorganic trace minerals had a greater (P = 0.03) antibody response to IBRV vaccination. Organic trace mineral supplementation improved growth performance of shipping-stressed calves compared with those fed equivalent levels of inorganic sources.