Entire Male Pigs

Table of Contents

1. Introduction
   1. Objectives
   2. Learning goals
   3. Teacher page
2. Entire Male Pigs
3. Castration of male pigs
   1. Statistics
4. Legislation and enforcement
5. Origin of boar taint
   1. Androstenone
   2. Skatole
6. Reasons for castration
   1. Increase the proportion of fat
   2. Increase consumer acceptance
   3. Reduce aggression
   4. Prevent unplanned breeding
7. Surgical castration
   1. Traditional surgical castration
   2. Anaesthesia combined with castration
   3. Gas analgesics
8. Problems related to surgical castration
   1. Animal welfare
   2. Pain and behaviour - the acute response
   3. Reduced growth rate and changed behaviour after surgery
   4. Health consequences
   5. Effect of age
   6. Consumer awareness
   7. Labour cost
9. Alternatives to castration
   1. Slaughter at lower weight
   2. On-line sorting
   3. Management
   4. Breeding and sperm sexing
   5. Perceptual masking of boar taint
   6. Immunocastration
   7. Immunocastration - physiology
   8. Immunocastration - practical implications
10. Completion
    1. Comments
    2. Self-assessment
    3. Key messages
    4. Further reading
    5. Evaluation
11. Acknowledgement

Health consequences

There is some evidence that surgically castrated piglets may be more prone to disease than gilts or entire male pigs (EFSA, 2004). Tielen (1974) reported that the prevalence of pneumonia is higher in castrates than in gilts, which was confirmed by an investigation of 18,000 pigs at a Dutch abattoir (de Kruijf and Welling, 1988).

The influence of castration on the immune system was demonstrated in a study by Lessard et al. (2002). They observed lower antibody responses in piglets castrated at 10 or 17 days of age and challenged twice with an antigen. Immunosuppressive effects of castration could be related to the stress reaction, inducing cortisol and catecholamine release, or to the lack of testicular androgens since these hormones are known to promote immunocompetence (the ability of the body to produce a normal immune response) (De Kruijf and Welling, 1988; da Silva, 1999).