Genetic approaches for rearing entire males
Résumé
Boar taint in the pork meat from entire male pigs results from the presence of two molecules: androstenone and skatole. The genetic determinism of androstenone and skatole has been studied for a few decades. It is well known that the heritability values are moderate to high and the genetic correlation between both levels is moderately positive. Nevertheless, application of selecting against boar taint has been limited in breeding schemes to obtain low boar taint lines. An important topic is the relationships between boar taint risk and other trait of economic interest. The genetic correlations with production traits such as growth rate, feed efficiency or carcass quality are mostly favourable, and selection applied in sire lines should tend to decrease boar taint. In dam lines, the genetic relationships with reproductive traits still need to be further explored. Some studies showed low correlations between boar taint risk and litter traits or fertility, but other evidences led to the conclusion that selection against boar taint would unfavourably impact female reproductive traits. Several issues have been addressed regarding potential criteria to predict boar taint at slaughter. One of the most promising has been human nose scoring at slaughter house, but relevant predictors are still needed that can directly be measured on live animals. New instrumental methods have to be developed for breeding purposes. In that respect, genomic information and a better understanding of genes involved in boar taint metabolism will provide useful tools for breeding entire males.