Behavioral and physiological performance of different gilt breeds during lactation

We evaluated the maternal behavior, physiology, and reproductive performance of both Damin (Min-pig x Large White) and Large White gilts to identify the advantages hybrid sows offer with regard to stress relieve and improvement of the welfare level of sows during late lactation. First-parity Damin gilts (n = 40) and first-parity Large White gilts (n = 40) were farrowed in individual pens. Video surveillance was used to monitor the occurrence of lateral recumbency and compare it to other postures, such as ventral recumbency, defecation, urination, tail posture, sham-chewing, and bar-biting behaviors. Monitoring was conducted from 07:00 to 09:00 h and from 13:00 to 15:00 h on days 3 and 6 of each week from the third to the fifth week post-parturition. In addition, the concentrations of tumor necrosis factor-alpha, interleukin-6, and salivary alpha-amylase were assessed. During the fourth week postpartum, Damin gilts showed a higher frequency of postural changes from lateral recumbency to other postures and less ventral recumbency, sham-chewing, and bar-biting behavior compared with Large White gilts. However, no significant differences were found between Damin and Large White gilts with regard to urination, defecation, tail wagging, and "tail low" behaviors. The concentrations of serum interleukin-6, salivary alpha-amylase, and serum tumor necrosis factor-a were higher in Damin gilts than in Large White gilts during the fifth week postpartum. Damin gilts partly achieve lower stress levels during late lactation and better animal welfare than purebred Large White gilts.