Raising entire males as an alternative to castration
The development of boar taint is affected by management, housing and feeding, but boar taint is not a focus in this review.
Alternative to castration
Male pigs in commercial production systems are often subjected to castration at an early age to prevent the development of undesirable odours and flavours in the meat. However, the practice of surgical castration raises concerns regarding animal welfare. Raising entire or intact males 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, and therefore also could be economically advantageous for the farming industry.
Key aspects in housing and management
In the housing and management of entire males the increased tendency for aggression and sexual behaviour must be addressed. Scientific evidence supports that four key areas in successful housing of entire males can be identified:
- Space allowance and group size: An increased space allowance for entire males does not reduce the level of aggression or sexual behaviour per se. However, space allowance becomes particularly important when it allows animals to avoid agonistic encounters and mounting and thereby reduces the risk for injuries.
- Feeding strategies: Studies indicate that feeding by a long trough, ad libitum feeding, feeding wet by-products, diets with a high level of amino acids, a good hygiene of the feeding and drinking place and sufficient water supply of the drinking system are associated with less sexual and aggressive behaviour and less skin lesions.
- Enrichment of the environment: Environmental enrichment, encompassing factors such as increased space allowance, access to straw bedding, provision of roughage, or outdoor areas, may not necessarily reduce agonistic interactions. However, enrichment occupies and distracts the animals from negative encounters. Moreover, bedding decreases the slipperiness of floors. Consequently, the risk for negative welfare effects such as skin lesions and lameness is lower.
- Group composition: A stable group composition is important when keeping entire males. However, rearing of litters without any mixing is difficult to implement in current housing systems. Mixing entire males with females is beneficial for the males, although from the point of view of the females, single-sex housing would be preferred.
Skin lesions, lameness and lack of appropriate enrichment are recommended as useful indicators during welfare inspection. Factsheets are currently developed for these indicators and become available in December 2023.
Building on the review, The EURCAW-Pigs website presents a new webdossier, as a central source of technical information and documents on this particular topic.
Introphoto: Undocked entire males in an enriched pen (©WUR)