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

Increase consumer acceptance

In a Danish consumer study, approximately 2 % of consumers gave a negative response in their evaluation of the eating quality of meat from entire male pigs, when androstenone concentrations were below 0.50 ppm in combination with skatole concentrations below 0.15 ppm (Godt et al., 1996). Sensibility to skatole and androstenone varies between people: most can register skatole but some (15 - 70 % according to international studies) are not able to detect androstenone (Støier, 2010).

Sensory analysis of boar taint in Danish laboratory.

The proportion of carcasses with androstenone and skatole concentrations above the commonly applied thresholds (1.0 ppm androstenone and 0.25 ppm skatole) was 30% and 11% respectively (Walstra et al., 1999). This was the average for six countries, although there was wide variation, presumably caused by breed, carcass weight and production system differences between countries as well as differences in analytical techniques.

A large study showed that European consumers in different countries had different attitudes to the taste of boar meat (Bonneau et al., 2000). British consumers were not critical of pork from entire male pigs whereas consumers in France, Germany, Spain and Sweden had a critical reaction. Matthews et al. (2000) speculated that in countries where a high proportion of pork is eaten in the form of products, the reaction to boar taint compounds is reduced because these compounds are masked.

It has been found that a single mating causes a rise in plasma levels of testosterone and androstenone, whereas it seems to require repeated copulations before the androstenone increase can be measured in boar fat. Lundström et al. (1978) found that when 120 kg boars observed other boars mating, it resulted in increased plasma testosterone and androstenone levels, but not in increased levels in carcass fat.