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

Entire Male Pigs

Surgical castration is painful to pigs and therefore the routine castration of male pigs is under discussion in Europe. Boar taint, the unpleasant odour of pork from a small proportion (less than 10%) of entire male pigs, is the main reason that is preventing the production of entire male pigs (Støier, 2010). The unpleasant odour is to a great extent affected by the presence of malodorous compounds like androstenone and skatole, which are stored in the fat tissue of some mature pigs. Other substances may also contribute. Boar taint is released when the fat on the carcass is heated. Across Europe, the majority of male piglets are therefore surgically castrated shortly after birth to avoid potential consumer rejection of meat because of boar taint. A very small proportion of female and castrated male pigs can accumulate skatole and develop an unpleasant odour. In the US the term "boar taint" is seldom used - it is called "sex odour".

Castration without any anaesthetics may be legally performed in European countries, with some exceptions (Switzerland and Norway). Economic advantages associated with the production of entire male pigs were demonstrated in the 1980s but in recent years consumer concerns for animal welfare have increased the pressure to find alternatives to castration.

Figure 1. Anatomy of the genital tract of male piglets and localization of incision during surgical castration (Adapted from Popesko, 1980).