Projekt ProSchwein Synthesebericht Projet ProSchwein Rapport de ...

Summary
ProSchwein
To date, male piglets are surgically castrated during the two first weeks of life without anaesthesia
in order to prevent the occurrence of boar taint in the meat which is mainly induced by
androstenone, skatole and indole. This method will be banned in Switzerland by 1 st January 2009.
Therefore, Suisseporcs launched the project ProSchwein in collaboration with the Swiss Veterinary
Office (SVO), the Swiss Federal Office for Agriculture (FOAG), the Swiss College of Agriculture
(SCA), SUISAG, COOP and Migros. ProSchwein investigated alternative methods to the
conventional castration of piglets and tested them under conditions of practice, i.e. methods based
on surgical castration with anaesthesia (inhalation anaesthesia, local anaesthesia, and injection
anaesthesia), methods without surgical castration (rearing entire male pigs, vaccination against
boar taint, genetic selection) as the economical impacts and the acceptance of the methods.
The test of an anaesthetic machine for inhalation anaesthesia (anaesthetic gas: isoflurane) with
some 300 piglets under conditions of practice showed that this method provides a good
anaesthesia for more than 90 % of the castrated animals if applied accurately and combined with
an injection against postoperative pain. It complied with the requirements regarding occupational
health and safety. The injection anaesthesia with ketamine/midazolam offers a potential alternative
to the inhalation anaesthesia. Preliminary results of field studies revealed a good effectiveness with
respect to pain relief. However, further investigations are required before this method can be
implemented (e.g. with respect to the registration of the anaesthetic). Within a study based on 47
piglets, a local anaesthesia conducted by a combined intratesticular and subcutaneous injection of
lidocaine significantly reduced pain during castration. An exhaustive pain relief was not achieved,
however.
The studies on rearing entire male pigs revealed a good feed conversion ratio and a high carcass
quality. The portion of carcasses with boar taint was at 6 % or more. According to the composition
of the feed ration, it was possible to reduce the content of skatole and indole but not the amount of
androstenone. The electronic nose developed by ALP Posieux is capable to detect between 95
and 100 % of the samples exhibiting boar taint according to the classical HPLC method at a
laboratory scale. For a thorough selection of tainted carcasses, further work is necessary in order
to detect all the compounds that contribute to boar taint including their interactions. The application
of the electronic nose in practice requires for technical adaptations which allow for operation under
the conditions of a slaughter house. As far as such an appliance is not available, and the control of
the amount of androstenone by means of genetic selection is not achieved, rearing entire male
pigs will probably remain a niche market.
The vaccination against boar taint prevents the production of androstenone and the occurrence of
boar taint in male pigs without surgical castration. This method is already used in countries such as
Australia, New Zealand or Brazil. The vaccine has been registered in Switzerland. Its registration
approval in the EU is expected during this year. In a study at the research station ALP Posieux, the
performance and the carcass quality of vaccinated animals were investigated. Vaccinated animals
exhibited a similar growth performance and a better feed conversion ratio and a higher carcass
quality compared to castrates. Additionally, the concentrations of androstenone and skatole in the
fat of the vaccinated animals were very low. Investigations within the subproject genetic selection
provide preliminary information on contents of androstenone, skatole and indole in the Swiss Large
White pig and on phenotypic correlations between the concentrations of these substances and
parameters on performance.
The investigations on economical impacts of alternative methods have shown that the alternatives
based on anaesthesia and the vaccination against boar taint can be recommended from an
economical point of view. The supplementary costs thereof (in the case of inhalation anaesthesia
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