Can ovariectomy be justified on grounds of behaviour?

Oestrogen-driven oestrous behaviour is normal for the equine species, but such behaviour is not always appropriate or convenient in domesticated horses – especially those used for competition. Oestrogen, in the absence of progesterone, drives reproductive behaviour, however progesterone can be regarded as the dominant partner in this hormone relationship and the presence of a patent corpus luteum will result in the non-receptive state of dioestrus. In the domesticated horse, overt reproductive behaviours are generally inconvenient and can affect performance. This is often described by owners as anything from a lack of concentration or frequent urination and “winking” during oestrus, to aversive behaviours such as bucking, kicking, and rearing. In extreme cases, owners may describe horses as being unmanageable or dangerously aggressive during oestrus.