Failure to establish normal maternal bonds occurs in individuals of many species. In some animals this may simply show as abandonment or refusal to care for offspring. An extreme behaviour, usually associated with litter bearing species, involves active maternal aggression towards newborns, up to and including infanticide. This behaviour has been observed in domestic sows (Harris et al., 2003) causing both significant economic losses to the pig industry and problems of animal welfare. Piglet mortality before weaning within commercial pig production is about 10% in Europe. One reason for these losses is sow aggression towards piglets (Lay et al., 2002). Aggression of sows towards their newborn offspring, a syndrome usually abbreviated by stockmen to ‘savaging’, has been described in large surveys of commercial piggeries in Europe with an incidence of 8% (Knap and Merks, 1987) and 7–12% (van der Steen et al., 1988). Harris and Gonyou (2003) also reported that the incidence came up with 5.3% of gilts in large study in the US. The behaviour may be defined as an active attack of piglets, using the jaws, that results in serious or fatal bite wounds. It almost always occurs during farrowing or immediately afterwards. The aims of this study were to investigate the incidence and nature of this behaviour and to compare other behaviours between savaging and non-savaging sows around parturition in 226 F2 sows that were produced by two highly divergent pig breeds of Chinese Erhualian and western Duroc with significantly genetic difference on maternal behaviours and were raised at three different pig farms. Each of these sows was housed in individual 2 m x 2.5 m pens with concrete floors. Three kilograms of fresh straw was provided to sows before parturition. Behaviour observations were made from 5 h before parturition to 24 h afterward using real time 1:0 sampling. Savaging sow was defined as an apparently deliberate attack on one or more piglets that resulted in the death, by biting, of at least one piglet. The incidence of savaging was: farm 1, 10.7% in gilts and 5.3% at the second farrowing; farm 2, 14.6% and 6.25%, respectively; farm 3, 6.8% at the second farrowing and 3.2% at the third farrowing. The incidence of savaging tended to be higher in gilts although some savaging gilts were killed before their second litters. There was no effect of the different farms on incidence of savaging. Prepartum nest building behaviours were not a predictor for savaging, but savage sows had a greater frequency of posture change from before parturition through the expulsive phase. This restlessness included an increase in rearing behaviour and a reduced ability to lie down carefully without endangering piglets. This study suggests that savaging is part of a more generalized behavioural pathology that includes increased excitability and is not specifically piglet directed.

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