Medical training in dairy heifers – A pilot study (2025)

de Boyer des Roches, A., Dumoulin, E., Roux, E. et al.

Abstract

Training is used in various species to reduce fear responses, ease handling, and improve welfare. This pilot study aimed to (1) design a positive reinforcement training program for dairy heifers, (2) monitor their learning performances and short-term memorization, (3) assess their long-term memory at one-year post-training, and (4) assess their behavior in new handling situations. We used 10 heifers randomly assigned to two treatments. TRAINED heifers (n = 5) underwent a training program including 19 husbandry and veterinary procedures split into 125 steps to be acquired over the course of 20 separate fifteen-minute sessions. The heifers had (median [1–3 quartiles]) 88 [62–100] commands and 80 [45–94] reinforcements per session. We used the ‘clicker training’ technique, with regular heifer concentrate as reinforcement. For each step, we established a learning criterion allowing to move to the next step, and we recorded the number of times the trainer gave the order (i.e. ‘command’) to the heifer and the number of times the heifer performed the correct behavior. CONTROL heifers (n = 5) were simply exposed to the handler’s presence. At one year after training, TRAINED heifers underwent the same procedures, and we recorded how many correct responses they produced out of 5 orders (or ‘commands’), together with a series of three behavioral tests: reaction to a motionless human, avoidance test, and ease-of-handling test. TRAINED heifers successfully learned 4 procedures (‘touching a target with the muzzle’; standing still calmly while being touched with: ‘arm-length glove’, ‘stethoscope’, ‘halter’) in (median) 1 session, 10 procedures (e.g. ‘eating from the hand’, ‘mouth opening and tongue manipulation’, ‘vaginal palpation’) in two sessions, 3 procedures (‘coming when called’, ‘tail lifting’, ‘rectal palpation’) in 3 sessions, and two procedures (‘standing still’, ‘left eyelid manipulation’) in 4 sessions. Results were similar when considering the number of commands required for learning. One year after training, four TRAINED heifers remembered 12–14 procedures, one heifer was able to only perform ‘eating from the hand’, and no heifers were able to perform ‘tail lifting’, ‘rectal palpation’, or ‘vaginal palpation’. At one year after training, TRAINED heifers were quicker to touch a motionless human, have a shorter avoidance distance, and require less time to be moved along the corridor than CONTROL heifers. Heifers can be clicker-trained for a large number of husbandry and veterinary procedures; they can remember most of the procedures one year later. Training may ease further handling.