Abstract. Three groups of beef cow and calf pairs were studied to determine plasma vitamin E and blood selenium (Se) concentrations of calves at 1 month old. Group 1 was managed on irrigated pasture and calves received no Se/vitamin E injections at birth. Group 2 was managed on irrigated pasture, and the calves were injected with Se/vitamin E at birth. Group 3 was managed on dry foothill grasslands, and these cows were supplemented with 56.3 mg vitamin E and 3 mg Se daily, and the calves received a Se/vitamin E injection at birth. The plasma concentration of vitamin E in group 1 and 2 cows (9.5 6 1.24 and 8.43 6 1.0 mg/ml, respectively) was significantly higher than that of the group 3 cows (2.28 6 0.42 mg/ml; P , 0.05). The blood Se concentrations in group 3 cows (169 6 37 ng/ml) were significantly higher than those in group 1 and 2 cows (36.4 6 15.9 and 31.1 6 12.5 ng/ml, respectively; P , 0.05). Calf Se was highly correlated to cow Se (r 5 0.965), and calf vitamin E was moderately correlated to cow vitamin E (r 5 0.605). Calf vitamin E concentrations were consistently lower than cow vitamin E concentrations, and many values would be considered deficient.

Weaning is generally regarded as a very stressful event in the life of calves, and is often associated with an increase in morbidity and reduced weight gain. Various management strategies are employed in an effort to reduce the impact of weaning on calf health and productivity. This study examined the effects of a nonspecific immune stimulant, mycobacterial cell wall (MCW), administered at or near weaning on the subsequent morbidity and growth of beef calves and assess the effects of a single dose of MCW on white blood cell parameters when given on the day of weaning. Heifer calves (n=137) were treated with either MCW or saline two weeks prior to weaning, while steer calves (n=60) were given either MCW or saline on the day of weaning and were monitored for 120 days. Results revealed that there were no observed differences between treatment groups in either weight gain or number of disease events. Under the conditions of this trial, administration of MCW at or near weaning did not have a significant effect on calf health or weight gain.