Review on keeping entire male pigs

The practice of surgical castration raises concerns regarding animal welfare. Raising entire or intact male pigs is an alternative to castration. In addition to offering an alternative to an aversive treatment, entire males offer several advantages in terms of improved feed efficiency, reduced feed intake and enhanced protein deposition. On the other hand, behavioural characteristics of entire males can lead to injuries and reduced welfare. Enhancing the welfare of entire males requires attention to key aspects in housing and management.

Behavioural characteristics of entire males are influenced by sexual hormones and include an increased tendency for activity, aggression and sexual behaviours such as mounting. It is important to focus on how to minimize negative welfare consequences of these behaviours during raising. The most important factors seem to ensure stable social relationships, enrichment of pen environments to satisfy the increased activity levels, and to create possibilities for avoiding agonistic attacks.

Animal- and resource-based indicators can help to identify welfare issues in entire males and these indicators can be used to facilitate welfare inspections on farms. Based on current knowledge, it is suggested to use skin lesions, lameness and lack of appropriate enrichment as indicators during inspection.