ABSTRACT
Crossbred calves (n = 350; average BW 240 ± 1 kg) were obtained from regional livestock auctions. Within each set (block, n = 4), calves were stratified by BW and arrival sex into 1 of 8, 0.42-ha pens (10 to 12 calves per pen). Pens were assigned randomly to 1 of 3 treatments consisting of supplemental Zn (360 mg/d), Mn (200 mg/d), and Cu (125 mg/d) from inorganic (zinc sulfate, manganese sulfate, and copper sulfate; n = 2 pens per block), organic (zinc amino acid complex, manganese amino acid complex, and copper amino acid complex; Availa-4, Zinpro Corp., Eden Prairie, MN; n = 3 pens per block), and hydroxy (IntelliBond Z, IntelliBond C, and IntelliBond M; Micronutrients, Indianapolis, IN; n = 3 pens per block) sources. During the 42- to 45-d backgrounding period calves had ad libitum access to bermudagrass hay and were fed corn and dried distillers grain-based supplements that served as carrier for the treatments. After removal of data for chronic (n = 6) and deceased (n = 1) calves, trace-mineral source had no effect on final or intermediate BW (P = 0.86) or ADG (P ≥ 0.24). With all data included in the analysis, dietary treatments had no effect on the number treated once (P = 0.93), twice (P = 0.71), or 3 times (P = 0.53) for bovine respiratory disease or on the number of calves classified as chronic (P = 0.55). Based on these results, trace-mineral source had no effect on total BW gain, ADG, or morbidity during the receiving phase in shipping-stressed cattle.
ABSTRACT
Utilizing groups of cograzed, naturally infected beef-type heifers, three fecal egg count reduction tests were conducted in the later months of 2007 at the University of Arkansas. Each test was 28 days in length consisting of individual animal fecal nematode egg counts and coprocultures. Both original and generic ivermectin injectable formulations were used in two of the tests at 0.2 mg/kg BW, with FECR percentages never exceeding 90% in either test. Oral fenbendazole was evaluated at 5 and 10 mg/kg BW, with FECR%'s exceeding 90% on all occasions, but with a precipitous drop when recently treated animals were treated at the lower dose. Evaluated in one test, injectable moxidectin given at 0.2 mg/kg BW resulted in egg count reductions of 96-92% (days 7 to 28). Also evaluated in one test, albendazole delivered orally at 10 mg/kg BW was 98% and 97% effective at 17 and 28 days post-treatment. For all tests, coprocultures conducted post-treatment contained only Cooperia spp. larvae (benzimidazole use), relatively unmodified percentages of Cooperia spp. and Haemonchus spp. larvae (ivermectin use), and primarily Cooperia spp. larvae with a small percentage of Haemonchus spp. larvae (moxidectin use).
