External testicles in domesticated animals are essential. Easy to snip off. Ever tried ploughing a field with oxen that haven't been gelded? Not fun. It's also

External testicles in domesticated animals are essential. Easy to snip off. Ever tried ploughing a field with oxen that haven't been gelded? Not fun. It's also a very convenient way to manage the breeding of livestock, ensuring some control of who breeds with whom. (It's also convenient to have external easy-to-remove testicles when one wishes to form certain choirs.)