Piglet castration with anaesthesia – what are the Dutch doing?

It was announced earlier in the year that Dutch supermarkets said they would only sell meat from farms where the male piglets have received anaesthetics prior to castration – what are the Dutch farmers actually doing?

There was an excellent study published by Haga and Ranheim (2004) from Norway that looked at the effects of administering a local anaesthetic and castration on the pain response in piglets, who had already been anaesthetised using a gaseous anaesthetic halothane.

Although the piglets were anaesthetised, they responded to stimuli such as injections of local anaesthetic into the spermatic cord (intrafunicularly) or into the testis and also to castration subsequently, by increases in their blood pressure, measured by an intra-arterial catheter. The results are summarised in Figure 1.

Figure 1. Blood pressure responses in piglets after injections of local anaesthetic and castration.

Interestingly, there was a response to injections either into the cord or more so into the testis, showing that the injections themselves induce some pain. However, when it came to castration the piglets not receiving local anaesthetic exhibited a much higher pain response (although they were under general anaesthesia) than the injected piglets. The pigs, which were injected into the testicle showed the least response.

When castrating calves (in my practice days) the intratesticular injection was extremely effective, but they were comparatively easy to inject due to their pendulous nature, unlike piglets.

In the UK, we do not castrate and our meat quality suffers for it because of boar taint. Currently, there are no local anaesthetics licensed for pigs, but they can be used under cascade.

There are also no signs of Improvac® from Pfizer yet – their new immuno-castration product – although it is hoped it will be available next year.

The EFSA is discussing piglet castration under welfare in November and it would be very useful to have a practical feed back from the Dutch vets and farmers on what they are doing and how they are getting on?