The diurnal variation of wool-biting behavior in housed sheep

Abstract

The abnormal oral behavior of sheep known as wool-biting is a serious animal welfare problem. In this study, we investigated the diurnal variation of wool-biting behavior under 2 density conditions (high density : 45 sheep, 1 sheep/m² ; low density : 24 sheep, 0.4 sheep/m²). The behavioral observation was taken for 5-minute at 10-minute intervals from 07.00 to 19.00 hours. The number of biting bouts, the number of bites within a bout, and the number of sheep performing wool-biting during each 5-minute observation period were recorded. The number of biting bouts, the number of bites, and the proportion of sheep performing wool-biting behavior increased significantly during the post-feeding period under both density conditions (P<0.05), but the number of bites per bout during that period was lower than that seen during the other periods (P<0.05). These results suggest that wool-biting behavior in sheep occurred mainly after feeding time and probably resulted from lacking of oral stimulations during feeding.