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

Management

Several studies have dealt with the influence of various feed components on skatole concentration in the intestinal content, faeces and back-fat of pigs. One of the major findings is that increased microbial activity leads to a decreased skatole production rate and a lower concentration of skatole in the digesta and the back-fat.

High-energy feeding has been shown to accelerate pubertal development and increase levels of both androstenone and skatole (Claus et al., 1994; Øverland et al., 1995; Zeng et al., 2002).

The feed composition affects the microflora in the intestines and may therefore influence the rate of skatole synthesis (EFSA, 2004). The effect of feeding on skatole production has been reviewed by Jensen and Jensen (1998) and Zamaratskaia (2004) and the concentration of dietary fibre is of great importance in changing the composition of the microflora in the hindgut.

Early studies suggest that skatole can be taken up through the skin (Hansen et al., 1994). When pigs were kept clean of faeces for just one week before slaughter skatole concentrations in the subcutaneous fat decreased significantly. High stocking rate and high temperatures alone do not increase skatole concentrations in back fat.