Influence de la pluie sur l'utilisation d'un abri par des taurillons au pâturage

The time spent under a shelter by 8 grazing fattening bulls of the Belgian Blue breed was recorded during 35 days using a time-lapse recorder with IR illumination. The observation period was divided into 166 hours with rain (20 %) and 674 hours without precipitation (80 %). An occupation rate was calculated for each hour as the sum of the time spent under the shelter by each of the 8 bulls divided by 480 (8 animals x 60 minutes). The average occupation rates were 15.4 +/- 29.1 % for the hours with rain and 4.5 +/- 14.8 % for the hours without precipitation (P<0.001). The occupation rate was significantly influenced by intensity and duration of the rain : the occupation rate being higher during rainfall than with dry weather when the intensity of the rain was at least 0.4 l/m2 and the duration more than 2 hours. There was no significant difference between the live weight gain of the animals with a shelter and of other bulls grazing on an adjacent pasture without shelter. Our observations suggested however that a shelter may improve the welfare of the animals.