Effect of an immunostimulant administered at or near weaning on weight gain and health of beef calves

Abstract

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.