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

Abstract

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), 1 (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 1 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. Les auteurs ont étudié les attaques subies par les porcelets à la naissance dans sept nouveaux gros éle-vages de truies nullipares. Les animaux ont été assujettis à un traitement visuel (éclairage continu ou diurne) ou sonore (vocalisation des nouveau-nés ou pas) à l'époque de la mise bas. Les auteurs ont observé le comportement de 6 625 cochettes hybrides à la première mise bas. Ils ont évalué le degré de sauvagerie, le nombre de porcelets atteints et les facteurs associés à l'agressivité de la mère envers sa progéniture. L'agressivité a été cotée 0 (aucune), 1 (moyenne) ou 2 (forte). Les auteurs ont ensuite examiné les effets de la lumière et du bruit, de l'emplacement de la cage dans le bloc de mise bas et de la durée (du premier au quatrième passage dans la stalle de mise bas). Trois cent trente et une cochettes (5,3 %) ont agressé leurs rejetons (cote 1 ou 2) et 201 (2,9 %) les ont tués. Trois cent quatre-vingt-douze porcelets (0,6 %) ont perdu la vie à la suite de ces attaques. L'incidence de la sauvagerie varie nettement avec les exploitations. Les décès attribuables à l'agressivité de la mère représentent en moyenne 11,2 % du taux de mortalité avant sevrage. Un éclairage continu diminue la proportion de truies nullipare causant des blessures mortelles à leur progéniture (P < 0,05), réduit de 40 % le nombre de porcelets par litière morts des suites d'une attaque (P <...

Savaging behaviour in gilts and sows

“…Most studies related to "savaging" are restricted to gilts (Marchant Forde 2002;Ahlström et al 2002), as piglet directed aggression is believed to be more frequent in young animals than in sows. In a previous study involving the first farrowing cycle, that is the initial period of approximately 5 mo when all breeding animals were gilts, on several new commercial farms, we reported that 2.9% of gilts killed one or more of their piglets (Harris and Gonyou 2003). A similar large-scale study is needed to assess the relative frequency of savaging by gilts and sows.…”

“…The third hypothesis was that sows that savaged during their first farrowing would be more likely to savage during their second parity than would those that did not savage as gilts (Lewis and Oakley 1970;Spicer et al 1985). The final hypothesis was that savaging incidence would be reduced by auditory and illumination modifications (Harris and Gonyou 2003).…”

“…Two environmental modifications were applied in the farrowing rooms. Animals were subject to either diurnal light (DL) or a continuous light (CL) treatment, and either a sound (SO; playback of newborn piglet vocalizations) or no sound (NS) treatment, applied to the rooms from approximately 3 to 5 d before until farrowing was complete within the room (see Harris and Gonyou 2003). Farm employees, who were generally present between 0700 and 1700, were responsible for data collection.…”

“…The facilities, animals used, and methods of data collection were described previously (Harris and Gonyou 2003). In brief, piglet-directed aggression at farrowing was studied on seven commercial farms during the first 9-10 mo of operation.…”

“…The incidence of savaging during their second farrowing between sows that had or had not savaged as gilts (hypothesis 3) was compared using Chi-square analysis. For the light and sound treatment comparisons (hypothesis 4), farm was considered an experimental block and rooms were the experimental unit [see Harris and Gonyou (2003) for additional details].…”