Savaging behaviour in domestic gilts: A study of seven commercial farms

Harris, M. J. and Gonyou, H. W. 2003. Savaging behaviour in domestic gilts: A case study of seven commercial farms. Can. J. Anim. Sci. 83: 435-444. Piglet-directed aggression at farrowing was investigated on seven large, new pig units. Gilts were subject to a light (continuous or diurnal light) and/or sound (newborn piglet vocalisations or no vocalisations) treatment around the time of farrowing. Behaviour records were collected for the first farrowing of 6625 crossbred gilts. The incidence of savaging, number of piglets affected by it and factors associated with piglet-directed aggressive behaviour were recorded. Piglet-directed aggression was scored as 0 (none), I (moderate) or 2 (severe). Effects of the light and sound treatments, situation of the farrowing crate within the farrowing room and time (from first to fourth fill of the farrowing rooms) were examined. Three hundred and thirty-one gilts (5.3%) displayed some degree of aggression towards their piglets (scoring either I or 2), while 201 (2.9%) killed piglets. Three hundred and ninety-two piglets (0.6%) were killed by savaging. There was marked variation among farms in the reported incidence of savaging. Savaging deaths represented on average 11.2% of total reported pre-weaning mortality. Continuous light resulted in a reduction in the percentage of gilts fatally savaging piglets (P < 0.05), reduced the number of piglets per litter killed by savaging by 40% (P < 0.05), and decreased total piglet mortality (P < 0.05). The sound treatment did not reduce piglet-directed aggression and in some cases appeared to increase it. Savaging decreased over time on 600 gilt but not 2400 gilt units.