Straw vs. peat as nest-building material - The impact on farrowing duration and piglet mortality in loose-housed sows

Provision of nest-building material pre-partum is required by farm animal legislation in Norway, but as some farmers have problems with straw in the slurry system, alternative and finer-grained substrates could be of interest. The aim of the present study was to examine the effects of providing different nest-building materials before farrowing (peat and long-stemmed straw) on farrowing duration and piglet mortality. Sows of Norsvin Landrace x Swedish Yorkshire were loose-housed in individual farrowing pens with their litter throughout the entire lactation period, and provided with peat (n=18), long-stemmed straw (n=17), or controls (n=18), fromtwodaysbeforeexpectedfarrowing untilfarrowing. Parityrangedfrom1to 9(mean ± SE:2.9 ± 2.0),of which 16 were gilts. The farrowing was video recorded, and the farrowing duration registered from first to last piglet born. Dead piglets were subjected to a post mortem. Sows provided with long-stemmed straw pre-partum had shorter farrowing duration compared to sows provided with peat or controls (P < 0.001). The percentage of stillborn piglets was also lowest among sows in the straw group compared to the other two groups (P < 0.001). Sows of parity ≥4 had longer farrowing duration than gilts and sows of parity 2–3( P < 0.001). Farrowing duration (P < 0.001) and the percentage of stillbornpigletsincreased(P