Betydelsen av social rang på beteende och mjölknings­parametrer i ett automatiskt mjölkningssystem (AMS)

Abstract: The purpose with the study was to find a pattern in the behaviour of dairy cows which could be related to their social rank. A behavioural study was conducted at the University Cattle Research Centre (Kungsängen) in Uppsala, Sweden. The study included 12 lactating dairy cows, 6 high ranked and 6 low ranked. The cows were housed in a loose housing barn with an automatic milking system (AMS) to which they had access 24 hours a day. During the experiment the total number of cows in the barn was 46. A forced cow traffic with pre-selection was used. The behavioural study included data from the automatic feeding- and milking system during 14 days and video recorded behavioural observations during 2 days. It was difficult to find significant differences between high ranked and low ranked cows due to a large variation in individual behaviour. However the high ranked cows tended to be milked more often between 06.00 h and 12.00 h, indicating it to be a more attractive time for milking. However, differences in eating behaviour could be observed. High ranked cows spent significant more time in the eating area and tended to visit the feeding stations more often than low ranked cows. Furthermore the high ranked cows tended to have a lower eating rate. However, the total feed consumption did not differ between cows with high or low rank. It was therefore suggested that low ranked cows were able to satisfy their nutritional needs but that they were forced to have a more efficient eating behaviour. The low ranked cows spent more time standing in the cubicles, probably to avoid confrontations with higher ranked cows. During the time just before milking, the low ranked cows were closer to the AMS when they were lying down. The reason might be that they want to observe the entrance so that they can find a way to get access to the AMS without confronting cows with higher rank. It was also observed that high ranked cows were further away from the AMS during the night, when they were resting. A possible explanation is that the cubicles that are most distant from the AMS are more attractive resting places, due to a less disturbant environment.