A systematic review of disease control strategies in beef herds, part 1: preweaned calf mortality.

Calves sold at weaning are the main source of income for cow-calf operations, and their survival should be a priority. Given this, the effective use of management practices for pregnant dams and calves to prevent calf mortality is essential; however, decision-makers often do not have access to information about the effectiveness of many management practices. A systematic review was conducted to summarize the evidence of the effectiveness of biosecurity, vaccination, colostrum management, breeding and calving season management, and nutritional management practices for preventing preweaned beef calf mortality. The population of interest was preweaned beef calves from birth until at least 3 months of age. The outcome of interest was general preweaning calf mortality with stillbirths excluded. Eleven studies were deemed relevant. Ten were observational cross-sectional studies, and one was a randomized controlled trial (RCT). The practices that were statistically significantly associated with calf mortality were intervening with colostrum in case a calf had not nursed from its dam or was assisted at calving, timing and length of the calving season, and injecting selenium and vitamin E at birth. More well-executed RCTs and cohort studies are needed to provide evidence of effectiveness and help support implementation of recommended practices in herds.