Relationships between sow and piglet traits in organic production outdoors and indoors

Summary

The aim of this study was to describe sow and piglet traits and the relationship between them in animals bred for conventional production kept in organic outdoor and indoor environments. 40 sows were studied during a seven week lactation. In parity one and three the sows farrowed outdoors (April to September) in huts and were moved to family grazing paddocks two weeks post partum (pp). In parity two and four the sows farrowed indoors (October to March) in individual pens and were moved to family pens with deep straw bedding two weeks pp. High backfat and weight loss during lactation was related to low piglet mortality and the relationship was stronger outdoors than indoors. Large litters had lower piglet growth than small litters and the relationship was stronger indoors than outdoors. Sows with larger litters were thinner and lighter at weaning than sows with smaller litters and the relationships were stronger outdoors than indoors. Our interpretation is that the outdoor environment stimulates sows to mobilise their energy reserves and produce milk, to a larger extent than the indoor environment does.