Effects of dietary fibre and feeding frequency on wool biting and aggressive behaviours in housed Merino sheep (2006)

Vasseur, S., Paull, D. R., Atkinson, S. J. et al.

Abstract

Wool biting is a behaviour that can develop in housed sheep, in which sheep start to bite and eat the wool of others. The aim of this study was to determine whether (i) supplementing the diet of housed sheep with fibre and (ii) increasing feeding frequency would help to reduce wool biting, aggressive behaviours and wool damage. In a 2x2 factorial experiment, 40 Merino wethers were either fed with lucerne-based pellets only, or with pellets supplemented with barley straw. They received their pellets either on a low feeding frequency basis (once a day Monday to Friday mornings, double ration on Friday afternoon, nothing Saturdays and Sundays), or on a high feeding frequency basis (twice a day, every day). The sheep were housed in 4 treatment pens, each with 10 animals. Wool biting and aggressive behaviours were recorded through direct observation and the sheep were scored for wool damage twice a week during the 15-week study. The provision of fibre had a significant effect on reducing wool biting (P<0.001) and wool damage score (P<0.001). There was no consistent effect of feeding frequency on wool biting or wool damage, and no fibre/feeding frequency interactions. Whereas wool biting in general increased with time during the study (P<0.001), levels of aggressive behaviour showed no consistent time trend, and there were no effects of fibre or feeding frequency treatments. It is concluded that wool biting is largely a redirected behaviour in concentrate-fed housed sheep deprived of adequate levels of activity or oral stimulus, and that the provision of roughage will reduce the development of wool biting and improve animal welfare in housed experimental sheep. From the results of this study, the 2 behaviours of woolbiting and aggression are different and the motivations resulting in their development are not the same. Incidents of aggressive behaviour were present throughout the study at a consistent level, whereas wool biting took time to develop and then increased. Furthermore, wool biting was not the sole preserve of 1 or 2 dominant animals in a pen, with all but 2 sheep acting as both initiators and victims of wool biting. The increase in wool biting during the course of the study was not only due to a fixed number of sheep increasing their habit, but also to new sheep undertaking the behaviour. This suggests that either the sheep may learn from each other by visual observation, or that there is individual variation in thecritical point from which the wool biting behaviour starts.