Groups of 17 sows each were grouped on day 40-50 of pregnancy and observed for two periods of 100 min each. They were assigned to two different treatments: (treatment S) grouped in the morning and observed immediately after; (treatment T) grouped in the morning after an injection of a tranquilizer (Azaperone) and observed immediately after. The animals in treatment S fought more frequently but with decreasing frequency. Fights amongst the T-sows were not eliminated and, moreover, increased during the second observation period. Despite these differences, the behaviour patterns displayed by the sows were essentially constant. Head-Head, Head-Body knocks, and Biting were the patterns more often used by the sow initiating the interaction in each treatment. The receiver animal responded most often with Head-Tilt and Retreat. The reasons for such differences in agonistic behaviour and the usefulness of tranquilizing the sows in relation also to their welfare are discussed.
Agonistic behaviour in grouped sows. III. Effects of grouping methods / D. Csermely; D.G.M. Wood-Gush. - In: BOLLETTINO DI ZOOLOGIA. - ISSN 0373-4137. - 57(1990), pp. 271-275. [10.1080/11250009009355707]