Ceballos, M. C., Góis, K. C. R., Parsons, T. D. 2020. The opening of a hinged farrowing crate improves lactating sows’ welfare. Applied Animal Behaviour Science 230, 105068.

Concerns about the welfare of lactating sows housed in farrowing crates have emerged because crates physically restrict the sows and possibly compromise their behavior and comfort. The aim of this study was to identify how the opening of a hinged farrowing crate on different days (4 or 7) post-farrowing impacts sow welfare. A total of 36 sows were studied. The sows were randomly allocated to 1 of 3 treatment groups: PC- crate remained closed until weaning (n = 13), T4- crate was opened on day 4 post-farrowing (n = 12), and T7- crate opened on day 7 post-farrowing (n = 11). Three different types of welfare indicators were used: behavioral (activity, posture and location-direction inside the pen), physical (udder and body lesions, lameness and body condition score) and physiological (salivary cortisol concentration). On days 3–8 post-farrowing, sow behavior was captured by continuous video recording of each individual sow daily from 6:00 h to 18:00 h. Sow behavior was observed using instantaneous recording (with a 2-minute fixed sampling interval) and focal animal as the sampling route. Salivary samples were also collected on these same days at 8:00 h. Lameness and body condition score (BCS) were evaluated when the sows were moved to farrowing pens and again when they were weaned, while skin lesions were evaluated on those days as well as on days 4 and 7 post-farrowing. After opening the crates (either at 4 or 7 days post-farrowing), we observed that sows utilized the additional space provided to them. Sows exhibited a ∼5 fold average increase in the number of different orientations and positions that they occupied in the pen after the crate was opened. Furthermore, sows also spent more time active and performing motivated behaviors such as interacting with their piglets and exploring the environment. Sows kept in pens with open crates also had less teats lesions on day 21 post farrowing compared to sows remaining in closed crates. Salivary cortisol concentration differed only on day 5 as the mean concentration for T4 was greater than T7, but neither differed from PC. Taken together, both behavioral and physical measures of welfare employed in this study indicate that the opening of a hinged farrowing crate contributes to improving the welfare of lactating sows.