How Can a Vaccine Control Boar Taint?

by 5m Editor
15 September 2008, at 2:40pm

GLOBE - The boar taint vaccine Improvac® works by stimulating the pig’s immune system to produce antibodies which temporarily block the function of the testes.

This dramatically reduces the amount of testosterone and the boar taint compound androstenone, both of which are released by the testes. These testicular compounds also inhibit the breakdown of another key boar taint compound, skatole; so the vaccine also encourages the elimination of this component of taint. The overall result of vaccination is a reduction in taint levels equivalent to that achieved by physical castration.

Safety vaccinator

The antigen (the active component) in the vaccine is a carrier protein linked to a small, synthetic molecule which is similar to a naturally occurring substance call GnRF (Gonadotrophin Releasing Factor), which controls the development and function of the testes in male pigs. When injected into male pigs the vaccine causes the immune system to produce antibodies to natural GnRF. Like many other vaccines, the first dose ‘primes’ the system and the second dose (a few weeks later) causes a significant surge in production of anti-GnRF antibodies. For as long as they are present, these antibodies effectively block the GnRF stimulation of the testes.

As well as controlling boar taint, the timing of vaccination, with the second dose only 4 to 6 weeks prior to slaughter, allows producers to obtain the benefit of efficient, boar-like growth for most of the fattening phase – something which is lost when piglets are physically castrated early in life.

Removing of the testes at the abattoir

Timing also helps avoid the problems of aggressive and sexual activity that can occur with entire boars in the late finishing phase. As a consequence of the reduction in testosterone after the second vaccination, boars become easier to handle and less likely to injure each other.

The vaccine is not a hormone or drug and, like other vaccines used to prevent disease, has a zero day withdrawal time, reflecting the absence of residue or food safety concerns.

Consumer taste panels in a number of different countries have demonstrated that the quality of meat from pigs managed using the boar taint vaccine has the same high eating quality as meat from female pigs and males that have been physically castrated.

Further Reading

- Go to our previous news item on this story by clicking here.