Document type: scientific article published in Applied Animal Behaviour Science
Authors: Bianca Vandresen, Jen-Yun Chou, Maria José Hötzel
Preview: Farrowing crates restrict sows' movement during farrowing and lactation, compromising their welfare and raising public concern. Unlike the gestation stalls, farrowing crates have been banned in only a few countries, yet many others have begun discussing phasing out this system. Scientific evidence on pig welfare should guide the transition towards sustainable farrowing housing systems, and it is essential to ensure sound scientific methodologies are in place behind the evidence. This systematic review, therefore, aims to investigate how sow and piglet welfare in different farrowing housing systems has been assessed in peer-reviewed empirical studies and to discuss the implications of animal welfare science for driving changes in farrowing housing systems. The current review did not include piglet crushing because this topic has been systematically reviewed. Literature searches in Scopus and Web of Science identified 708 articles, of which 65 were retained after screening for inclusion criteria. Loose farrowing pens, group housing, outdoor farrowing, hinged crates, and ellipsoid crates were identified in the reviewed literature as alternatives to the conventional farrowing crates. The parameters used to measure animal welfare were based on behaviour, physiology, performance, and health. No study investigated the impacts of farrowing housing systems on emotional indicators of sow welfare, and studies rarely assessed the sow-piglet interactions. Within the same housing type, studies varied in their design and management practices (e.g., bedding and enrichment provision), which made cross-study comparisons difficult. Based on the existing evidence, more research is needed to determine which alternative farrowing system promotes better overall sow and piglet welfare. This systematic review identified structural knowledge gaps in the scientific assessment of pig welfare in farrowing housing systems. We propose how future research can address these gaps and how study designs should focus on specific housing aspects to allow an overall conclusion on the effect of farrowing housing systems on pig welfare. We also highlight the importance of considering the public's expectations while meeting the needs of animals and producers so that the proposed alternative farrowing systems can be sustainable and prevent economic losses for the pig industry's supply chain in the long term.
