Étude cas-témoin des données comportementales des nourrisseurs de lait automatisés chez les veaux laitiers sains ou malades
Case-control study of behavior data from automated milk feeders in healthy or diseased dairy calves
Résumé
Group housing of preweaning dairy calves is increasing in popularity throughout the dairy industry. However, it can be more
difficult to individually monitor calves to identify disease in these group systems. Automated milk feeders (AMF) not only provide
producers with the opportunity to increase the milk allowance offered to preweaning calves but they can also monitor individual feeding
behaviors that could identify calves at increased risk of disease. The objective of this retrospective case-control study was to determine
how feeding behaviors change in preweaning calves leading up to and during a disease bout. This study was conducted between fall
2015 and fall 2016 on 2 commercial dairy farms in Ontario, Canada. Producers’ treatment records for respiratory or enteric illness were
used to identify cases. Control calves were selected from calves not treated for disease and matched on the days on the AMF. Both farms
housed calves in dynamic groups of 9 to 11 calves with an AMF and fed milk replacer. Differences in feeding behaviors, including milk
consumption, drinking speed, rewarded visits, unrewarded visits, and total visits to the AMF per day, were analyzed by mixed models
accounting for repeated measures. Data were analyzed for the 7 d before, the day of, and 7 d after treatment. A total of 28 cases and 28
control calves (n = 56) were analyzed. Calves with disease consumed significantly less milk than their healthy counterparts, beginning
5 d before disease and until 3 d after disease detection. Sick calves had fewer unrewarded visits starting 3 d before until 2 d after illness
detection. Sick calves drank significantly more slowly starting 4 d before illness detection until the day after illness detection compared
with healthy controls. No differences were found between cases and controls for rewarded visits. Calves on a high plane of milk nutrition
significantly alter feeding behaviors before illness detection. Data from AMF on feeding behaviors may help to detect disease earlier in
preweaning dairy calves.