The welfare of pigs in two farrowing/lactation environments: cortisol responses of sows

Abstract

Plasma free cortisol concentrations were measured in 24 primiparous sows housed from Day 104 after mating up to Day 2 after parturition. Concentrations were measured in 22 of these sows, from Days 2–29 of lactation, housed in either commercial farrowing crates (Crate treatment) or farrowing pens with straw added (Pen treatment). The mortality and growth data of litters from the time of birth to weaning were also recorded. The mean plasma free cortisol concentration was higher in sows housed in the Crate treatment, compared with sows housed in the Pen treatment, on the first day of treatment (8.2 and 5.8 nmol l −1, respectively, P < 0.05) and on Day 28 of lactation (5.6 and 4.0 nmol l −1, respectively, P < 0.05). The data suggest that housing treatment around parturition and during lactation may have only limited effects on the welfare of sows, providing that lactation is no longer than 28 days. On Days 21 and 24, there were no effects of treatment on free cortisol concentrations and no response to the exogenous adrenocorticotrophic hormone (ACTH), respectively. However, on Day 28, there were mean increases in the concentrations of free cortisol of approximately 150% and approximately 60%, respectively; these may have been the result of unavoidable attention of the piglets to the sows.