Parturient behaviour and offspring-directed aggression in farmed wild boarof three genetic lines

The farming of 'alternative' species such as wild boar is becoming increasi ngly common in western agriculture. Relatively little has been published ab out the behaviour of wild boar in captivity, and data about parturition and maternal behaviour are particularly scarce. Twenty-four primiparous farmed wild boar females of three genetic lines (SD, San Diego; PK, Peter Kalden, S, Scandinavian) were videotaped before and during parturition, and produc tion data were recorded. Sows were housed in individual, well-strawed pens measuring 3.05 m x 1.52 m. The duration of parturition, duration of inter-b irth intervals (IBIs), frequency of posture changes before and during partu rition and nature of parturient behaviour were recorded. Offspring-directed aggression displayed by the sows was scored as 0 (none), 1 (moderate) or 2 (severe). A score of 2 indicated that a sow killed one or more of her youn g and/or human intervention was required to control her aggression. Mean +/ - S.D. litter size was 5.4 +/- 1.5 young. Mean +/- S,D, duration of parturi tion was 81.4 +/- 79.2 min. Litter size and duration of parturition did not vary with genetic line. Eight sows (33.3%) showed some offspring-directed aggression; of these, two killed one or more of their young. Aggression sco re varied with sows' genetic line: SD sows (62.5% of which scored I or 2) w ere more aggressive than either PK (22.2%) or S (14.3%; P < 0.05), and only SD females exhibited severe aggression. Parturition lasted longer in sows scoring 2 (mean +/- S.E. duration = 211.8 +/- 27.3 min; n = 4) than those s coring either 0 (56.0 +/- 13.7 min; n = 16) or 1 (52.8 +/- 27.3 min; n = 4; P < 0.001). Similarly, IBIs were longer in sows scoring 2 (mean +/- S.E. I BI = 51.6 +/- 9.5 min) than those scoring 0 (13.1 +/- 4.8 min) or 1 (12.7 /- 9.5 min; P < 0.01). Sows scoring 2 changed posture more often (mean S.E. changes = 65.8 +/- 12.0) during parturition than those scoring 0 (12.3 +/- 6.0) or 1 (2.8 +/- 12.0; P < 0.01). These findings contribute to our limit ed understanding of maternal behaviour in wild boar. and may be useful in h elping to explain savaging behaviour in domestic sows. (C) 2001 Elsevier Sc ience B.V. All rights reserved.