We will be posting a new series of common myths in horse keeping. Today's topic is the proud cut gelding. Geldings that retain stallion-like behavior after castration are often referred to as 'proud cut.' This means that the veterinarian left part of the epididymis (a reproductive structure adjacent to the testicle) and the concern is that this tissue continues to produce testosterone and the associated hormonally driven behaviors.
In fact, the epididymus is not responsible for testosterone production so even if some tissue remains, it would not be responsible for the behavior. The more likely scenario is that the gelding has learned behaviors. It is also possible to have 'cryptorchid' stallions where a testicle retained in the abdomen is still producing testosterone. It is not considered the veterinary standard of care to remove just one testicle so it would be rare to find such a stallion.