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

Introduction

Welcome to this learning resource on entire male pigs!

It has been known since the Middle Ages that meat from a small minority (up to 10 %) of entire male pigs has an unpleasant odour, the so-called boar taint. The sensibility to boar taint is different between consumers and it can only be detected by some of the consumers and mainly when the pork is heated (Støier, 2010).

Problems with boar taint are nevertheless the primary reason for castration being routinely performed on the majority of male pigs in commercial meat production. Castration also results in reduced aggressive and sexual behaviour between pigs and a higher proportion of fat in carcasses.

Entire male pigs are preferred for meat production for several reasons. They are more efficient than castrates at converting feed into lean meat and, because they are slaughtered at an earlier age, they have less negative impact on the environment. However, castration has economic drawbacks in that it impairs growth for some days after surgery and involves extra labour. In recent years knowledge about the pain and animal welfare issues related to castration, and consumer concerns, have focused greater attention on the castration of male pigs.

In this learning resource we will explain the reasons for boar taint, consider methods of detecting and measuring boar taint, and discuss the alternatives to castration. The point of departure is that all stakeholders prefer entire male pigs with high meat quality, rather than castrated pigs. We will discuss the dilemma of poor welfare associated with castration (pain and risk to the health of the animals) and the poor welfare of uncastrated pigs farmed in confined spaces (stress and fighting, resulting in skin lesions and ultimately carcass damage).

The scientific report on the animal welfare aspects of the castration of piglets has been peer-reviewed by the members of the Scientific Panel for Animal Health and Welfare (AHAW) for the European Food Safety Authority (EFSA). The report was adopted in 2004.

Entire male pig. Source: Ulla Schmidt.