Dimensions of maternal behaviour characteristics in domestic and wild x domestic crossbred sows

We examined the maternal behaviour of seven domestic and seven wilds domest ic primiparous sows during 10 days post partum to investigate two questions : (1) Did maternal behaviour change during domestication? (2) Can the inter individual variability of maternal behaviour be subsumed into a few dimensi ons of maternal temperament? We recorded: (a) willingness to leave the nest for food on Day 2; (b) reaction to a playback of squeezed piglet distress vocalisation on Day 2; (c) spontaneous nursing behaviour and spontaneous ly ing-down behaviour on Day 5 (from an overnight video recording); (d) reacti ons to playbacks of various piglet distress vocalisations on Day 6 and (e) reactions to a human in the 'nest' with piglets on Day 9. Moreover, data on baseline cortisol saliva concentration and its increase during a brief tra nsportation period and novel environment challenge at the age of 5 months w ere available. Crossbred sows did not differ from domestic ones in any aspe ct of maternal behaviour except for a higher tendency to terminate final ma ssage during nursings and a higher frequency of changing posture from lying to standing and back during the night. Factor analysis (based on correlati on matrix of 11 behaviour and cortisol variables calculated for all 14 sows after removing the effect of breed) indicated that 82% of the variability in the data could be explained by three factors: first, 'calmness' on which low night time frequency of major posture changes, carefulness of lying-do wn behaviour and high propensity to remain in nursing position after milk e jection loaded positively while cortisol concentrations during challenge lo aded negatively; second, 'protectiveness' with high loadings of the reactio n scores to the playbacks of piglet distress calls and the human presence n ear the piglets; and third, 'nursing activity' which was strongly positivel y associated with nursing frequency, and negatively with the proportion of nutritive nursings and baseline cortisol values. The results indicate that most aspects of pig maternal behaviour have not been significantly changed by domestication and that substantial variability in maternal behaviour exi sts between sows, perhaps in the form of several behaviour characteristics which encompass both behaviour and endocrine profiles of the sows. (C) 2000 Elsevier Science B.V. All rights reserved.