Myth Busting Boar Taint

Boar taint is one of those pork industry issues that seems to be discussed at length, everyone has an opinion about it and certainly polarises industry when it comes to eliminating it. The consumer has a number of names for boar taint (interestingly and not surprisingly, boar taint is not one of them) including piggy or porky smell, and off-taste. Boar taint is a perspiration/urine and facecal like odour/flavour in pork from entire male pigs. The major compounds responsible for boar tainted pork are androstenone and skatole, and both compounds are accumulated in fat. The only effective method of eliminating boar taint is by castration of entire male pigs either by (i) surgical castration or (ii) administration of the boar taint vaccine Improvac?(Pfizer).

I am continually surprised by the misconceptions regarding boar taint and its management that continue to be affect our industry. So in the next section of this article Iwill myth bust some of these misconceptions regarding boar taint and its management.

A recent APL study (2011) reported a high incidence of entire male pigs from multiple sites in Australia that exceeded the international sensory threshold of 1µg/g for androstenone, and 0.2µg/g for skatole. D’Souza et al. (2011) found that the incidence of carcases with androstenone >1µg/g from was >28%. Pfizer have conducted in excess of 35 studies globally, and the incidence of pork from entire male pigs exceeding the consumer sensory threshold of >1µg/g for androstenone and 0.2µg/g for skatole was 39% and 15% respectively.

Anecdotal observations from a number of Australian supply chain managers suggest use of lower carcase weights may minimise the boar taint risk. This however is not the case (D’Souza et al., 2011) as the correlations between hot standard carcass weight and androstenone and skatole concentrations (Figures below) were weak. Hence the use of carcase weight selection strategies to minimise the boar taint risk in entire male carcases are not appropriate.

The inclusion of non digestible carbohydrates results in increased carbohydrate fermentation in the hind gut rather than protein, and this may lower production of off-odour compounds including skatole due to reduced tryptophan fermentation. The addition of non digestible oligosaccharides, fructo-oligosaccharides or inulin, in the diet of pigs has resulted in a decrease in skatole levels in backfat (Claus et al., 1994; Hansen et al., 2006). Dunshea and Macauley (2009) reported that inulin supplementation in entire male pigs had minimal effect on androstenone and skatole concentrations in fat. The data to date indicates that feeding non-digestible carbohydrates is not viewed as viable in entire male pig production systems due to the lack of impact on androstenone concentrations. However, a 2011 press release (Rasmussen, unpublished) from the Aarhus University, Denmark reported on a study that entire male pigs fed chicory had higher levels of a liver enzyme that metabolises skatole and androstenone, resulting in lower fat skatole and androstenone content.

Recent work from the Danish Meat Research Institute (Tørngren et al., 2011) indicates that processed pork would need to have androstenone levels lower than 0.4µg/g and needed to be served at below 23°C for it not to be detected by consumers. Given the fact that the average androstenone levels in Australia (2011) for porkers and baconers was 0.73 and 1.1 µg/g respectively suggests that processing of pork from entire male pigs into ham and bacon does not mask boar taint. As far as serving ham and bacon cold, maybe OK for ham but no thanks on the cold bacon!

And finally whilst not a myth, I often get asked as to the status of low boar taint genetic lines and semen sexing as possible strategies to minimise boar taint. A number of genetic companies in Europe are looking at selection strategies to develop low boar taint pig genotype. Although not yet commercialised, it would appear that any selection of low boar taint pigs would have a negative effect on growth performance. Hence, such a strategy might not be commercially viable given the current cost of feed. In the case of semen selection, this may be a viable technology however this technology is far from commercially viable.