Abstract
This study aimed to investigate how farrowing and rearing systems affect skin lesions, serum cortisol, and aggressive behavior as indicators for weaning stress of piglets. Between May 2016 and March 2018, in total 3144 weaning piglets from three different farrowing systems were examined: farrowing crates (FC), single-housing free-farrowing pens (FF), and group-housing of lactating sows and litters (GH). After weaning and regrouping, piglets were relocated to conventional rearing pens (conv; 5.7 m2) or to wean-to-finish pens (w-f; 12.4 m2). Skin lesions were scored 24 h after weaning. Blood samples were taken one week before and 24 h after weaning to analyze the individual difference in serum cortisol. Behavior was observed for 24 h after relocation. Animals raised in FC and FF had significantly more skin lesions than that of GH animals. Piglets born in GH showed lower cortisol differences and fought less and for shorter periods compared to FC and FF piglets. Piglets weaned to w-f pens showed greater cortisol changes and fought significantly longer than piglets in conv pens. Group housing during the suckling period reduced weaning stress for piglets in terms of skin lesions, serum cortisol, and aggressive behavior. Greater space allowance (w-f vs. conv) was not beneficial with regard to the investigated parameters.