Open access publications in the SLU publication database

Abstract

This thesis is based upon two studies performed in the experimental barn at Kungsängen Research Centre, Swedish University of Agricultural Science (SLU), Uppsala, Sweden. The barn is equipped with an automatic milking (AM) system and is designed for 56 cows. During the studies the herd consisted of 45-50 cows of the Swedish Red Breed. Day in lactation and number of lactation varied among the cows participating in the studies. The objectives of the first study were to investigate which traffic system was optimal for the cows activity, and if there were differences in behaviour and activity depending on social rank. Three traffic systems, free traffic (FT), forced traffic (FO) and selective traffic with controlling gates (SE), were compared. Visits to the feeding area and to the milking unit were distributed at quite regular intervals throughout the day, since feed was available all day. The results indicated that FT was advantageous for the cows, since number of cows in the milking queue was lower and numbers of meals were higher compared to FO and SE. However, the number of cows fetched for milking was lower and the milking frequency was higher during FO and SE. Number of cows fetched did not depend on social rank, however, the low-ranked cows spent less time resting and feeding and more time in the milking queue compared to the high-ranked cows. These effects was higher the more forced the traffic system was. The objective of the second study was to test the hypothesis that cows choose equally between left and the right side when lying. The cows were observed in the loose house system provided with AM and both cows and pregnant heifers were studied when out on pasture. When kept indoors the cows chose equally between left and right laterality. In the resting area the cows lay facing towards the activity area in approximately 60% of the observations. While out on pasture, cows and heifers which were in the ninth month of gestation chose the left side in 60.7% of the observations.