Fattening of entire male pigs under organic conditions – Influences of group composition on injuries and behaviour

Summary

Fattening of entire male pigs prevails as an alternative to castration of male piglets. Entire males show more agonistic and mounting behavior than castrates, which can be a cause for skin lesions and lameness. Previous studies have mainly been carried out in conventional housing systems. However, organic housing conditions differ in terms of litter availability, space allowance and outdoor run. Here the question was investigated, how under organic housing conditions (according to the label of Bio Suisse) single-sex groups with entire males (EE) differ from mixed-sex groups with entire males and females (EF) and from mixed-sex groups with castrates and females (CF) with regard to lesions, lameness, agonistic behavior and mounting. Group size was 20 animals. On day four, 51, and 110 after regrouping and start of the fattening period, animals were assessed for lesions and 10 focal animals per pen were observed via video recording. On day 51 and 110 there were slightly more skin lesions in the EE-groups compared to the CF-groups. Entire males (in the EE- and EF-groups) showed clearly more agonistic and mounting behavior than castrates. EE and EF didn’t differ, neither in terms of lesions nor in behavior. Prevalence of lameness was low in all groups. This study indicates that under organic housing conditions single-sex groups with entire males and mixed groups with entire males and females are equivalent with regard to animal welfare. Yet, entire males showed also under those more spacious conditions more agonistic and sexually motivated behaviour, which has caused a higher number of superficial skin lesions. Higher space allowances offer escape opportunities which might be the reason why not more serious lesions and lame animals occurred. So far there are neither in organic nor in conventional animal husbandry specific regulations for fattening of entire male pigs. Our findings, however, indicate that more generous housing conditions would allow entire males to show their natural behaviour without serious injuries.