Weaning management of beef calves with implications for animal health and welfare

Weaning is a necessary husbandry practice in which nutritional, social, physical and psychological stressors are imposed on the beef calf causing alterations in behavioural and physiological responses. The present paper is a review of studies on the influence of weaning stress at housing on beef calves. To date, few studies have examined the effect of weaning on the extended physiological and immunological responses of beef calves and cows. Studies indicate that weaning in combination with immediate housing decreased total leukocyte numbers, reduced in vitro production of interferon-gamma and increased concentrations of acute phase proteins compared with deferring housing for 35 days post weaning. In cows, transitory neutrophilia (increase in neutrophil number) and lymphopenia (decrease in lymphocyte number), reduced interferon-γ production, and increased concentrations of acute phase proteins were evident post weaning, whereas post-housing, changes were less marked. Thus, there is a greater transitory reduction in immune function biomarkers in calves immediately post weaning. These immune biomarkers may be used in the future to help identify animals susceptible to weaning stress and that are more likely to succumb to respiratory infection