Sexualverhalten des Amerikanischen Präriebisons (Bison bison bison) unter mitteleuropäischen verhältnissen

Objective: Bisons (Bison bison) have only recently being bred in central Europe for economic reasons. Therefore, knowledge about the behaviour of the species comes almost exclusively from North American animals under semi-natural conditions. As such, it cannot be guaranteed that the knowledge will be applicable to the behaviour of central European animals. Material and methods: The sexual behaviour of the North American bison was studied on two farms in Germany. During the rut the herds consisted of five rsp. two bulls and 52 rsp. eight cows. The behaviour study lasted from the end of April rsp. beginning of May to the beginning of November rsp. end of October in 1998 rsp. 1999. The herds were observed several days per week. The daily survey lasted from dawn till dusk and differed due to the season in its duration. Results: The peak of the rutting season was reached in the first week of August. Bulls and cows showed the same behavioural patterns as are already known from cattle. A certain rank-positioning among the bulls did exist at least concerning the first position. The most dominant bulls copulated more often than the sub-dominant ones. Approximately 50% of the cows were served only once; on average 1.8 copulations per oestrus were counted. Most rutting activities occurred around noon and in the afternoon. Conclusions: Concerning the sexual behaviour no aspects were found which would count against the economical use of the bison in central Europe. Clinical relevance: To ensure that calves are not born during the winter and therefore are exposed to freezing conditions, bulls and cows should temporarily be held separately. The use of large ranges will minimize the risk of injury from aggressive interactions by providing the necessary avoidance distance for subdominant individuals.