[Effect of an oral sedative on the behavior and the zootechnologic performance of fattening bulls of the white-blue Belgian breed].

This trial was conducted with 22 Belgian White and Blue double-muscled cattle (body weight: 241.5 +/- 6.2 kg; age: 7 months). Two similar groups were constituted: a group of bulls which were treated with potassium bromide (BT; n = 11) and another one which remained untreated (UT; n = 11). The treatment (736 mg potassium bromide/kg feed dry matter) was stopped 60 days before the slaughtering day. The treatment with potassium bromide induced a significant reduction in the rear engagements during the whole trial period (221 days), in direct attacks during the period A (from day 0 to day 53) and in side-on attacks during the period B (from day 54 to day 167). The daily weight gains, calculated for the whole trial period, were not significantly different between the two groups. Feed utilization was lower in treated bulls. During the period C (from day 168 to day 221), the sedative potency of potassium bromide seemed to be weaker than during the periods A and B. This might be due to the habituation to potassium bromide. On the basis of these results, we can conclude that the frequency of rear engagements and, during a restricted period of fattening, the frequencies of side and direct attacks are significantly reduced when potassium bromide (736 mg/kg feed dry matter) is used. The time spent for hay intake, the frequency of water intake (even if the time consumed at the drinking trough was the same) was reduced and the time during which the bulls were standing was prolonged by bromide.