Effects of Different Farrowing and Rearing Systems on Post-Weaning Stress in Piglets

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.

Effects of Different Housing Systems during Suckling and Rearing Period on Skin and Tail Lesions, Tail Losses and Performance of Growing and Finishing Pigs

“…In accordance with a previous study of Lange et al [ 10 ] and our first hypothesis, mainly the farrowing system affected the occurrence of skin lesions at regrouping occasions (here: week 1 and week 6) with GH piglets showing fewer skin lesions after weaning and regrouping for fattening than piglets born in FF or FC. According to the findings of Lange et al [ 10 ] but against our hypothesis, FF piglets in the present study did not fully benefit from the loose farrowing system, showing no differences in skin lesions compared to FC pigs. In week 1, significantly more Conv-GH pigs were scored 0 for skin lesions than Conv-FF and Conv-FC pigs.…”

“…For example, when these pigs were grouped, the new hierarchy was established sooner than in groups of less socialized pigs resulting in less skin lesions. These findings were confirmed by a previous study of Lange et al [ 10 ] who investigated the effects of housing systems during suckling and wean-to-finish-rearing on post-weaning stress 24 h after weaning and relocation in terms of skin lesions, serum cortisol and aggressive behavior. Several studies show that loose-housing of sows during lactation, even in groups, can be a feasible alternative to confined housing systems: free farrowing not only improved the welfare of the sow, but also positively influenced the piglets in terms of behavior and performance [ 11 , 12 , 13 ].…”

“…The weaning process, often accompanied by mixing, is considered as the first major stressful event in a piglet’s life [ 1 ]. Regrouping inevitably leads to hierarchical fights, causing skin injuries and negatively affecting animal welfare [ 3 , 5 , 7 , 9 , 10 ]. In the present study, undocked piglets reared in the farrowing pen in particular seemed to benefit from the absence of regrouping at weaning.…”

“…For each assessment, the two persons were present; one being the assessor, the other one an active observer, who justified the given score. The same scoring approach for the three-staged lesion score was used, as published by Lange et al [ 10 ]. During the rearing period, pigs were scored every two weeks for skin lesions.…”

“…To the authors’ knowledge, almost no scientific publications are available concerning rearing in the farrowing pen. The previous studies of Gentz et al [ 22 ] and Lange et al [ 10 ] showed the potential of alternative housing conditions, but both stated that further investigations are needed as, for example, Lange et al [ 10 ] did not study long-term effects. Long-term effects of the housing system during suckling period on the regrouping behavior at the beginning of the fattening period are scarcely studied.…”