Which method is most commonly used?

Worldwide, surgical castration is still by far the most used. Immuno-castration to a much lesser extent because it is expensive, labor intensive for the pig farmers and not accepted everywhere in the market (sales parties fear negative reactions from consumers).
In Europe, the number of non-castrated pigs has increased considerably in recent years. Much information is available from international research about housing methods and best practices. Pig farmers can thus achieve an animal friendly rearing of boars. Additionally, good detection methods have to ensure the quality of the meat.