If boars are not castrated, the result is an increased number of carcasses that emit an unpleasant hog smell. In order to avoid this smell, the boars are castrated before they are 2-7 days old. Danish law requires pain relief in connection with castration and intensive research work is being performed in order to avoid castration in the long term.

The production of non-castrated boars results in an increased number of carcasses that emit hog smell when the meat is prepared. The hog smell is characterised by a urine or manure-like odour.

The biological background for the hog smell in boars is primarily due to two chemical compounds – androstenone and skatole. Skatole is the result of microbial metabolism in the intestines and can be changed through the feed. Androstenone is a pheromone (not a hormone) that is produced in the testicles and the safest way to avoid hog smell is therefore to castrate the suckling pigs.

Danish law contains specific requirements for pain relief

The law in Denmark requires that castration of suckling pigs is performed withpain relief and as early as possible within the animal’s first 2-7 days. When the pigs are seven days old, castration must be performed under anaesthetic.

The castration must only be performed by a veterinarian or a person educated in castration and who has experience in castration of suckling pigs through suitable means and under hygienic conditions.

Several research projects are trying to find new solutions

In Denmark, among others SEGES, the Knowledge Centre for Pig Production under the Danish Agriculture & Food Council, has for many years tried to solve the problem of hog smell in pork but a safe solution has not yet been found. Tests have been made with breeding, feed, gender sorting of sperm cells, the vaccine Improvac and "on line” sorting of carcasses through the "human nose” method where you smell at all carcasses and remove those with odour. None of these solutions are safe or are accepted by the markets where we sell our pork.

The EU Commission has requested all EU countries to address in writing the risk factors for tail biting before tail-docking can be performed. This constitutes a tightening of the current rules and means that the pigs must not be tail-docked as a matter of routine. In Denmark, a tightening has been made of the documentation requirement for tail biting before the performance of tail-docking. Therefore, the breeder must perform a comprehensive risk assessment and prepare an action plan before performing tail-docking.