A note on differences in nursing behaviour on pig farms employing individual and group housing of lactating sows

Abstract

The sow nursing behaviour may be affected by housing environment. So far, studies have focused on within-farm experimental comparisons, but data comparing nursing behaviour in a sample of commercial farms using different housing systems are lacking. This study had the following goals: (I) To compare sow nursing behaviour in a sample of farms with group housing (GH) and individual housing (IH) systems for lactating sows with piglets. (II) To quantify the variability in nursing behaviour attributable to between-farm differences. (III) To document the decline in maternal nursing investment in GH and IH during the last 2 weeks before weaning. The observations were carried out in five GH (6–11 sows kept in a large pen) and in five IH (each sow kept in a small pen) commercial farms. Nursing behaviour of four focal sows per farm was recorded for 6 h in two lactation periods (fourth week, 1 day before weaning; weaning = 5.5 weeks on an average). There was no significant difference between GH and IH farms in total number of nursings, in number of nutritive nursings or in proportion of nursings initiated by the sows. However on GH farms sows terminated higher proportion of nursings ( p = 0.05) and allowed piglets’ post-ejection massage for shorter time ( p = 0.02). Nursing synchronization was higher among sows on GH than on IH farms ( p = 0.006). The proportion of variability attributable to the between-farm differences ranged between 6 and 30% for the individual nursing behaviour variables. The effect of lactation period was not significant for any of the variables suggesting that maternal investment was not declining between weeks 4 and 6 in either environment.