They didn’t. It was the pig that came. However, to attempt to more seriously answer your question, all I can find on the subject is this https://skeptics.stackexchange.com/questions/6611/do-pigs-have-30-minute-orgasms which appears to indicate that in most cases the 30 minute number is based on more than one emission. However, the source is a bit old and the links to university and government sites appear no longer valid.