Press release Alternatives to castrating pigs without anesthesia are gradually finding their way into Europe.

"Variety is an advantage, and consumers like the alternatives".

No one alternative has emerged regarding surgical castration of piglets without anesthesia. Depending on the desired meat product and market demand, immunocastration, anesthetized surgical castration, and non-castration (in combination with workable boar taint detection tools) are valid options that can coexist in Europe. Consumers are not reluctant, concludes the European network (COST IPEMA) on alternatives to piglet castration. ILVO, other knowledge centers and stakeholders from all over Europe participated in the IPEMA network.

An undesirable odor or taste

Boar taint is an unpleasant smell or taste in pork or fat from about 4% of intact boars. In order to avoid this undesirable odor or taste, as well as the aggressive and sexual behavior that boars can exhibit, until recently male piglets were routinely castrated (without anesthetisia). This practice came under increasing societal pressure. In response to these concerns, the European pig industry committed itself to stop the practice from 2018 onwards, on the condition that a number of practical and economic bottlenecks in working with intact boars, immunocastrates or applying anesthesia and/or pain control would be solved.

Meanwhile, the deadline has passed and in a number of European countries, including the Begian region of Flanders, are keeping varying numbers of intact boars. Flanders, as an exception to the rule in Europe, also made a partial transition to immunocastration. In other countries, however, the search for feasible alternatives is only now beginning (see figure). In order to promote knowledge-sharing and exchange of experiences within Europe, the COST IPEMA action was set up. In this action, knowledge and points of view were exchanged in the field of nutrition, welfare, genetics, reduction and detection of boar taint, meat quality and consumer acceptance. The most important lessons were presented in an online closing conference.

Important steps taken in the detection of boar taint

An important prerequisite for the pig sector to switch to intact boars was the development of rapid detection methods for boar taint in slaughterhouses. Much progress has been made in this area. Sensory detection of boar taint by humans is already successfully applied in slaughterhouses all over Europe. However, the selection and training of the 'noses' is still a focus of attention. There is good news: an instrumental detection method for skatol and androstenone, two chemical components of boar taint, has recently been developed in Denmark. Marijke Aluwé (ILVO): "This method looks promising and could accelerate the transition to intact boars.

Avoiding boar taint through management and genetics

To avoid boar taint in intact boars, feeding strategies and management aimed at reducing stress are successful. Genetic selection is also possible and can most easily be applied to the boar line. A number of 'low boar taint' lines have already been introduced to the market. If a carcass at the slaughter line tests positive for boar taint, it is possible to valorize it in processed meat products. This can be up to 50% in some products, in combination or not with proper seasoning or smoking.

Meat quality challenges for intact boars

Meat from intact boars is leaner, the fat is more unsaturated and is therefore softer than that of barrows (castrated male pigs). This makes it less suitable for certain meats, such as dried hams. Adjustment via adapted feed is achievable to a certain extent. In addition, genetic selection to a higher intramuscular fat content is necessary.

Reducing aggressive and sexual boar behavior

Finally, to limit aggressive and sexual behavior in intact boars, unlimited feeding and housing in stable groups with sufficient space and natural enrichment (scattering) are good measures. Moreover, to prevent unwanted early pregnancies, it is best to separate intact boars from gilts. Selection against undesirable behavior is possible, but is currently not a priority in breeding programs.

Immunocastrate performance

The meat quality of immunocastrates is much less of a challenge and the risk of boar taint is also greatly reduced. By extending the time span between the 2nd vaccination and slaughter (6 to 7 weeks instead of 4 weeks), the meat quality can be adjusted even further. However, the impact on the technical, and therefore economic, performance must be taken into account.

High consumer acceptance of the alternatives

The pork sector is very concerned that consumers will find it difficult to accept meat from immunocastrates. This has been nuanced by a survey conducted by ILVO within the framework of IPEMA. In total, 4,700 European consumers in 16 countries, with 417 Belgian consumers participating. If they are informed about the vaccine and why it is used, 71% of European consumers would accept meat from immunocastrates. Immunocastration is therefore the second most accepted alternative to non-anesthetized castration. Only castration with anesthesia and/or pain relief does better (acceptable for 85% of consumers). Meat from intact boars is okay for half of the consumers (50%), but meat from unanesthetized castrated pigs is only acceptable for one-third (32%).

Marijke Aluwé (ILVO): "These results raise the question of why most European pork chains are reluctant to apply immunocastration. More insight into the attitude of all stakeholders and of the importing countries is needed. The option of surgical castration with anesthesia and/or pain relief should not be written off either. In addition, a better acceptance of intact boars can be expected if boar taint free meat can be guaranteed by application of accurate detection methods".

All alternatives side by side

The most important conclusion during the IPEMA online closing conference was that the various alternatives can and should exist side by side. After all, there are quality differences between barrows, intact boars and immunocastrates. This diversity makes it possible to respond to the different quality requirements on the market. Marijke Aluwé (ILVO): "An example: for high quality Spanish hams such as Iberico you need fattening pigs that weigh more than 140 kg. These quality requirements cannot be met with intact boars.

Efforts are still needed to get the alternatives off the ground in Europe. The housing, selection, management, meat quality and feeding strategy for intact boars needs to be further optimized. A joint approach by all chain partners is necessary.

More info

• Read more about IPEMA and review the closing conference at www.ca-ipema.eu.
• Read more about piglet castration and the alternatives on the Varkensloket website: www.varkensloket.be/dierenwelzijn#castratie.
• On 28 September Evert Heyrman defends his doctorate: 'Farm specific strategies for the reduction of boar taint'. Supervisors of the PhD are Prof. Dr. Nadine Buys and Dr. Steven Janssens of KULeuven and Dr. Marijke Aluwé of the Flanders Research Institute for Agriculture, Fisheries and Food. A press release will also be sent about that doctorate.