Domestic animals are usually castrated in order to avoid unwanted or uncontrolled reproduction ; to reduce or prevent other ways of sexual behavior such as territorial behavior or aggression ( like fighting between groups of uncastrated males of a species ) ; or to reduce other consequences of sexual behavior that may make animal husbandry more difficult , such as fence destruction when animals try to get to nearby females of the species . Domestic animals are usually castrated to avoid unwanted or uncontrolled reproduction ; to reduce or prevent other manifestations of sexual behavior such as territorial behavior or aggression ( e.g. fighting between groups of entire ( uncastrated ) males of a species ) ; or to reduce other consequences of sexual behavior that may make animal husbandry more difficult , such as boundary\/fence\/enclosure destruction when attempting to get to nearby females of the species .