Impact of farrowing system and prepartum nest-building material on nest-building behaviour and farrowing in sows

Farrowing crates are widely used as the main housing system for farrowing and lactating sows on commercial farms although they have a negative impact on sow welfare and behaviour. One of the main reasons for using farrowing crates is to reduce piglet mortality during farrowing and lactation. We compared the effects of temporary crating (TC) versus free farrowing (FF) with different nest -building materials on production and welfare measures. Sows were investigated using a 2 x 3 factorial design. Sows were allocated to two farrowing treatments: FF sows were not crated around farrowing, and TC sows were crated from 2 days before expected farrowing until 3 days after farrowing, when the crate was opened. In both farrowing treatments, the nest -building material was given from 7 days prior to farrowing as follows: (1) 1 L of straw twice per day, (2) 1 sheet of newspaper twice per day or (3) fastened jute fabric to the farrowing crate. The study consisted of two parts; part 1 included a total of 87 sows for data on piglet mortality and growth, and part 2 included data on nest -building and farrowing behaviour from a subset of these sows (n = 34). Farrowing treatment affected piglet mortality; FF sows had a lower number of stillborn piglets than TC sows (P = 0.04), but the number of crushed piglets was higher (P < 0.01). Nestbuilding material tended to have an impact on total number of crushed piglets (P = 0.08) and piglets that died during 3 days of lactation (P = 0.09). Litter growth was better in the FF group than in the TC group from piglet age of 1 day to 3 weeks (P = 0.04). Overall, little nest-building-related behaviour occurred, probably due to the small amount of nest -building material. The usability of the nest -building material varied with farrowing treatment; FF sows used newspaper most for nest -building, while TC sows used straw and jute fabric (P = 0.01). There were no differences in the piglet birth intervals or the farrowing duration. In conclusion, free farrowing can have positive effects on piglet growth but negative effects on piglet survival in early lactation. Different nest -building materials have different effects depending on the type of farrowing system. (c) 2024 The Authors. Published by Elsevier B.V. on behalf of The Animal Consortium. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).