Training cows to approach the milking unit in response to acoustic signals in an automatic milking system during the grazing season

The aim of the present study was to examine whether cows in a commercially-managed barn with automatic milking can learn to visit the milking unit in response to an acoustic signal during the grazing season. The study included 10 Swedish Red and White dairy cows, randomly selected from a herd of 45 cows housed in a barn with an automatic milking system. A small box emitting an acoustic signal was attached to the collar of the 10 cows. During the training period, the signal was induced manually from a distance and during the evaluation period, signals were activated automatically from a computer connected to the automatic milking system. The cows were trained indoors using an operant conditioning technique. All cows had 12 training sessions with 7–12 signals given at variable intervals. An evaluation period followed the training period. During evaluation, the trained cows received an individual signal when 8 h had passed since the previous milking. These cows received another signal after 10 h if they had not visited the milking unit. The signal was activated regardless of their location. During the last training session, 8 of the 10 cows approached the milking unit more often following a signal than after a control period with no signal (P < 0.05). There was a greater probability for the cows to respond to the signal if they were indoors (P < 0.05). The average milking interval for cows trained and evaluated in early season was 8.2 ± 0.44 h (±S.E.M.). The interval for a reference group (with no signal) in early season was 9.7 ± 0.18 h (P < 0.05). The intervals were 8.7 ± 0.56 h and 9.0 ± 0.20 h for the five cows trained in late season and a reference group (with no signal), respectively. During the evaluation in a full herd situation, the response ranged between 15 and 75% for individual cows. Low levels of reinforcement at the milking unit may have compromised responsiveness.