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

Prevent unplanned breeding

In commercial pig production, where females are reared for meat production and often slaughtered at around 110 kg live weight, a significant percentage of them may reach puberty.

At high slaughter weights (over 100 kg) there is a risk that female pigs may become pregnant before slaughter (Andersson et al., 1999; Rydhmer et al., 2006), especially if they are slow-growing, for example from outdoor systems.

Entire males are more likely than castrates to display sexual behaviour, such as mounting (Cronin et al., 2003; Rydhmer et al., 2006).

Mounting behaviour. Source: Kerstin Lundström.

Castration at birth reduces mounting behaviour to the level seen in females. After castration at the age of 30 days, mounting behaviour, as in intact males, persists for another month despite the lack of testes - but then declines (EFSA, 2004).