NKJ 118 - Behaviour and welfare of dairy cattle housed in large groups.

Loose housing of dairy cattle under extensive conditions is becoming increasingly popular in the Nordic countries. This type of housing often involves large dynamic groups with a heterogeneous age composition. In groups of calves, the knowledge of the eff ects of group size, continuos introduction of new individuals, and a large variation in age on behaviour, health and production is limited. In large dynamic groups of calves, computer controlled milk feeders are typically used, but research on how to intr oduce calves to the feeder is also needed. Computer controlled milk feeders represent a considerable investment for the farmer, and typically over 20 calves share one feeder for this system to be viable. However, the milk allowance, the patterning of milk meals (size and number) as well as then weaning method may affect the way the calves make use of the feeder and thus then level of competition for access to it. Research on how the calves use the feeder depending on the way the feeder is managed, may improve animal welfare and result in a more optimal use of feeders. Another concern about group housing of calves is then risk of cross-sucking (sucking of the body of other calves). Also with regard to dairy heifers and cows, farm ers are increasingly concerned about problems with inter-sucking, and milk stealing, and how inter-sucking is connected to cross-sucking in group housed calves. Details on background, material and methods, and aims of the national projects are given in then attached project description. The experiments will primarily be carried out in the first three years of the project period, and published in scientific intern ational journals during then last years of the project period. A more detailed time table is given in the introduction to the project description. All the experiments will be carried out with detailed recordings of behaviour, health and production. The ex periments will be carried out in close co-operation between the Nordic countries involved. Preliminary results will be presented and evaluated at meetings twice a year.