Open access publications in the SLU publication database

Abstract

When automatic milking is combined with grazing the cows are given a unique opportunity to choose between being indoors or outdoors. Concerns have been raised about achieving sufficient number of milkings per day since the cows’ motivation to be milked is low and cows are expected to go to milking voluntarily. The overall aim was therefore to examine how management routines affect cow motivation to visit the milking unit several times a day. First it was hypothesised that distance to pasture and level of supplements affects the milking frequency. The results demonstrated that cows with a shorter distance to pasture had a higher milking frequency during the first part of the grazing season and a higher milk yield compared with cows pasturing further from the barn. One important finding was that cows on the distant pasture changed their behaviour as the grazing season progressed and almost ceased to walk to their pasture area. A high level of silage supplements compared with a buffer feed offered in the barn had no affect on the milk yield. Also there was no affect on the number of milkings during the first part of the grazing season but during the latter part, cows with a high level of silage had a lower number of milkings. It was also hypothesized that it is possible to strengthen the cows’ perception of a feed reward in the milking unit by training the cow to respond to a conditioned stimulus, an acoustic signal. Most of the cows learnt to approach the milking unit following the signal when they were in an enclosed area of the barn, close to the milking unit. However, when receiving the signal out on pasture the response to the signal was variable and comparatively low. Finally, the hypothesis that enhanced sensory stimulation during milking by feeding or stroking the cows’ abdomen affects the level of the oxytocin and cortisol during milking was tested. Feeding during milking increased the plasma oxytocin level and milk production whereas brushing during milking depressed the milking-related release of cortisol, possibly inducing an anti-stress effect.