Long-term effects of castration, chronic intermittent social stress, provision of grass silage and their interactions on performance and meat and adipose tissue properties in growing-finishing pigs.

ABSTRACT

In order to assess chronic stress in entire and castrated male pigs and to describe effects of a provision of grass silage in those pigs, a 2 × 2 × 2 factorial experiment comprising the factors castration, chronic intermittent social stress and provision of grass silage was carried out with 147 growing-finishing pigs from 25.6 to 102.1 kg body weight. The experimental design allowed investigating interactions between the three factors, but only few were statistically significant. Stress exposure consisted of repeated short-term confrontations with unfamiliar pigs and short-term separations. Carcasses of stress-exposed pigs had thicker backfat, lower lean meat percentage and a different fatty acids composition of the adipose tissue. While entire males differed strongly from castrates in performance, carcass characteristics and adipose tissue properties, we found no evidence for an increased level of chronic stress in entire males compared to castrates. Provision of grass silage increased stomach weight and reduced dressing percentage, but did not impair performance, adipose tissue properties or meat quality.