Influence of grouping strategy on welfare measurements of organic entire male pigs

Summary

Alternatives to surgical castration in organic pig production are needed, due to stress and pain caused by castration of male pigs. One alternative, which is in accordance with the values in organic farming, is production of entire male pigs. However, changed behaviour of entires compared to castrates might affect the welfare of the animals. Therefore, in order to produce entire male pigs, without compromised animal welfare, changes in the production system, possible offered by the organic farming system, with e.g. more available space and access to rooting material and roughage, might be a necessity. The aim of this article is to investigate the effect of grouping strategy and group size on levels of mounting behaviour and skin lesions, hypothesising that procedures that influence the social stability (e.g. regrouping) will have a larger negative effect in small groups compared to large groups. Approximately 1400 organic entire male pigs of the breed (Landrace x Yorkshire) x Duroc were reared in parallel in five organic herds, distributed across four batches in a 2x2 factorial design, with two grouping strategies; regrouping and relocation and two group sizes; 15 and 30 animals. Animals were able to socialise in the lactation period, they were all mixed with unfamiliar pigs at weaning, and a second mixing occurred at insertion to fattening pens for pigs being regrouped. Counting of skin lesions and registration of mounting behaviour were done on three occasions during the experimental period.