Biosecurity in dairy calf production: A scoping review

Infectious diseases pose a persistent threat across all stages of the dairy production chain, with calf rearing being particularly vulnerable due to the calves' immature immune systems. Effective biosecurity measures are crucial in mitigating the risk of pathogen introduction and spread among calves. The recent influenza outbreak in U.S. dairy herds underscores the need to evaluate biosecurity practices employed in calf rearing. This scoping review aims to provide a comprehensive overview of reported biosecurity practices and the knowledge and attitudes of calf producers on biosecurity. By identifying existing gaps and areas where further research is essential, the review seeks to enhance biosecurity protocols, ultimately reducing the risk of infectious disease transmission and improving the overall health and productivity of dairy calves. Peer-reviewed studies that reported on biosecurity practices or assessed the knowledge and attitudes of producers in intensive farming systems were included. Out of 983 identified citations, 49 studies were included, mainly from the U.S., Canada, Australia, and Ireland, with a focus on Holstein calves. Internal biosecurity measures, such as calf housing and colostrum management, were widely studied, while external practices, such as isolation and quarantine of new animals, pest control, and sanitization of incoming vehicles and equipment, were underrepresented. To a lesser extent, the attitudes and knowledge of producers regarding biosecurity practices were also explored, highlighting the importance of early care practices. This review emphasizes the significant variability in how biosecurity practices are reported in dairy calf production studies, with only 23 % explicitly identifying practices as biosecurity measures. Prior studies focus predominantly on internal biosecurity measures, particularly during the pre-weaning period, underscores their critical role in calf health. This review supports a need for standardized frameworks for reporting biosecurity practices and more research into producers' attitudes and knowledge to enhance biosecurity implementation and calf health.