Effect of sward height and distance between pasture and barn on cows' visits to an automatic milking system and other behaviour

Two experiments were conducted to study the effects of sward height (experiment I) and the distance between barn and pasture plot (experiment II) on cows’ visits to an automatic milking system (AMS) and other behaviour. The study was carried out in a situation in which grazing was combined with fully automatic milking. The cows had to visit the system voluntarily without interference of the farmer. The AMS was continuously available in the barn adjacent to the pasture. The pasture was divided into ten plots of 1 ha for the two experiments and the preceding habituation. The same group of 24 Holstein Friesian cows was used in both experiments. The cows were allowed to spend up to 15 h at pasture daily. The results of experiment I (rotational grazing) showed that the total number of AMS visits increased from 4.4 to 7.3 and that the number of milkings increased from 2.6 to 3.0 when sward height decreased (P<0.01). The results of experiment II (strip grazing) showed that a distance of 360 m between pasture and barn did not affect the cows’ visits to the AMS. In both experiments, cows preferred to lie in the pasture, when available, rather than in the cubicles, and tended to visit the barn group-wise and to enter the AMS in close succession. As a consequence, in the period that the cows had access to the pasture there were peaks in AMS visits, and the AMS was unvisited for several hours.