The farmers decided to perform castration on the male pigs to control their population on the farm.

castration 是名词，来自动词 castrate（阉割）。castrate 源自拉丁语 castrare，意思是"切除睾丸"。castration 指通过手术或化学方法去除雄性动物的生殖器官，以达到控制繁殖或改善肉质的目的。