Graduate Student Literature Review: Social and feeding behavior of group-housed dairy calves in automated milk feeding systems.

Automated milk feeders (AMF) allow farmers to raise calves in groups while generating individual records on milk consumption, drinking speed, and frequency of visits. Calves raised in groups benefit from social interaction, which facilitates learning and adapting to novelty. However, calves in large groups (>12 calves/feeder) experience a higher risk of disease transmission and competition than those housed individually or in smaller groups. Therefore, if group size, grouping strategy, and disease detection are not optimal, the health and performance of calves can be compromised. The objectives of this narrative literature review, from publications available as of February 2023, are to: 1) describe the use of AMF in group housing systems for calves and the associated feeding behavior variables they automatically collect, 2) linking feeding behavior collected from AMF to disease risk in calves, 3) describe research on social behavior in AMF systems, and 4) introduce social networks as a promising tool for the study of social behavior and disease transmission in group-housed AMF-fed calves. Existing research suggests that feeding behavior measures from AMF can assist in detecting bovine respiratory disease (BRD) and enteric disease (ED), which are common causes of morbidity and mortality for pre-weaned dairy heifers. AMF records show reduced milk intake, drinking speed, or frequency of visits when calves are sick. However, there are discrepancies between published research about the sensitivity of feeding behavior measures as indicators of sickness, likely due to differences in feeding plans and disease detection protocols. Therefore, considering the influence of milk allowance, group density, and individual variation on the analysis of AMF data is essential to derive meaningful information used to inform management decisions. Research using dynamic social networks derived from precision data show potential for the use of social network analysis (SNA) to understand disease transmission and the effect of disease on social behavior of group-housed calves.