A systematic review of the impact of housing on sow welfare during post-weaning and early pregnancy periods

Abstract

Breeder animals are an important focus in farm animal welfare assessments as they typically live the longest lives and are at the greatest risk for suffering due to their longevity. For breeding pigs, the time between the end of lactation (post-weaning) and the implantation of embryos (early gestation) is very dynamic from both a physiological and husbandry perspective. However, research to date is limited on how best to house and manage sows during this critical period of their production cycle from a welfare perspective. Previous animal-based welfare outcome measures were restricted to certain health, behavioral and physiological indicators. This systematic review used Web of Science to make in-depth comparisons among welfare-based studies that focus on sow housing during the post-weaning and early pregnancy period to identify important knowledge gaps. Only a small number of studies (n = 27) were found that met our systematic search criteria. Compared to stalls, group housing requires mixing of animals and always triggers more aggression and skin lesions at the time of mixing. The predominant use of health and physiological indicators constrained the animal-based welfare outcomes in these studies. Thus, what type of housing yields the best overall welfare outcome remains to be elucidated as none of the studies found explored the mental wellbeing of sows during this period. This systematic review defines a critical knowledge gap regarding the full impact of housing on the welfare of post-weaning and early gestation sows. This gap, and thus the true welfare impact of sow housing, will only be addressed by the use of novel, more holistic assessment methods that also capture the psychological state of the sow.

A systematic approach to defining and verifying descriptors used in the Qualitative Behavioural Assessment of sows

“…Once presented with Table 1. A final list of descriptors modified from the Welfare Quality® assessment protocol for pigs, including groupings used during the focus group discussion based on word similarity the definitions, experts participated in a mock QBA session, where they scored four randomly selected, 1 min 40 s videos of sows within a novel arena taken from an ongoing study (Chou & Parsons 2022). Experts were instructed to complete QBA based on the representative definitions to test their efficacy.…”

Gilts prefer an open pen to a stall

“…As previously noted in a systematic review on sow housing, the assessment of psychological or affective states is a critical gap in the literature 6 . Preference tests (i.e.…”