Effect of a trainer cow on health, behavior, and performance of newly weaned beef calves

Experiments were conducted to investigate the effects of the presence of a trainer cow on behavior, performance, health, and feeding patterns of newly weaned beef calves. In Exp. 1,252 weaned calves (270 +/- 18 kg) were alloc ated to 22 pens (11 to 15 calves per pen). A trainer cow was randomly assig ned to each of 11 pens. Calves were weighed prior to feeding on d 0, 3, 7, 14, 21, and 28. Rectal temperatures were taken on each of these days (excep t d 28) and blood samples were collected on d 0, 3, and 7 and subsequently analyzed for serum haptoglobin and leukotoxin antibody titers. Instantaneou s scan observations of calf behavior were made at 10-min intervals between 0130 and 1730 on d 1, 2, 4, 5, and 6. A similar protocol was used in Exp. 2 , in which 291 calves (258 +/- 17 kg) were allocated to 24 pens. Blood anal yses included haptoglobin, white blood cell counts (WBC), and neutrophil:ly mphocyte (NL) ratios. In Exp. 3, the above protocol was followed and patter ns of feed bunk attendance of individual calves were also monitored using r adio frequency identification by passive transponder ear tags. Trainer cows did not influence (P >.10) calf rectal temperatures, requirements for anti biotic therapy, WBC, NL ratios, or leukotoxin antibody titers. Pooled acros s treatments, NL ratios were lower (P <.01) on d 0 (.31) than on d 3 (.36) or d 7 (.39). Although differences in weight gain were detected in some per iods within the three experiments, there were no differences (P >.10) overa ll (d 0 to 28). Trainer cows did not affect (P >.05) frequency or duration of bunk visits by the calves. Averaged across treatments, frequency and dur ation of bunk visits increased (P <.001) from 9.6 visits/d and 56.7 min/d b etween d 0 and 3 to 12.3 visits/d and 108.9 min/d between d 15 and 21. The number of calves observed eating during scan sampling observations also inc reased from 16.4% on d 1 to 2536 on d 4 (P <.10) and 29% on d 5 and 6 (P <. 05). More (P <.05) calves were observed lying on d 1 (41.7%) and d 2 (45.3% ) than on d 3 (37.5%), d 5 (34.8%), or d 6 (36.2%). With a trainer cow pres ent, fewer (36.7% vs 41.5%; P <.001) calves were observed lying and more (1 1.7% vs 10.2%; P =.08) were observed walking than when no cow was present. Trainer cows did not improve calf health, time spent at the feed bunk, or p erformance of newly weaned calves.