Here are some facts about testosterone and how it affects behaviour:
What you should know about the effects of castration:
Sometimes, very shortly after castration, some dogs become temporarily manic/reactive. When a male dog is castrated, the testicles are surgically removed under a general anaesthetic. It is the testicles that produce most of the testosterone. As soon as the dog has been castrated, testosterone production stops. However, the pituitary gland appears unaware of this fact and continues to send signals (LHRH – luteinizing hormone releasing hormone and FSH – follicle stimulating hormone) to trigger the testes to produce more testosterone. As the testes are no longer there to do the job, of course, no testosterone gets produced but the pituitary gland continues to produce increasing levels of LHRH and FSH. Eventually, after a week or so, the pituitary gland stops trying to send these chemical messages. In the meantime, LHRH and FSH have been produced in higher quantities than is usual and it is thought this it is these chemicals that can sometimes lead to increased reactivity in the newly castrated dog. It is useful to be aware of this so that you can be more understanding and try to mitigate these behaviours with careful management.
What behavioural changes will I see in my adolescent male dog?
Adolescent male dogs will start to become more interested in other entire (not neutered) male and female dogs. Adolescent puppies may start to sniff other dogs’ urine marks and pee over them. At this age most male dogs will start to ‘cock’ their leg to urinate, especially when doing small ‘marking’ wees rather than emptying their bladder.
There is often a breakdown in recall training at this stage as the dog becomes more aware of his surroundings and more confident in being away from his owners. Well socialised dogs that have interacted well with other dogs can start to show posturing behaviour such as stiff body language, raised hackles and tail, and placing their neck over another dog. If the other dog does not have the skills to diffuse the tension, scuffles can break out.
Adolescent males may start to mount and ‘hump’ other dogs, which again can lead to fighting.
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Along with positive socialisation, training and appropriate nutrition, castration is often considered a key component of responsible dog ownership. However, in recent years, attitude towards castration has changed slightly, both from a veterinary and an owner’s perspective.
From a medical point of view, castration has some benefits but also some downsides, so the decision should be made on a case-by-case basis. Castration can be beneficial in preventing specific testosterone-related diseases and can help in the management of some behavioural issues. However, there are some negatives: castrated animals have an increased tendency to obesity and some conditions are more prevalent in gonadectomised dogs, such as incontinence, osteoarthritis and some neoplasia. These conditions are clearly multifactorial, but research suggests disruption to the hypothalamic–pituitary–gonad axis and excessive gonadotrophin release as a possible component.
For the pet owner, preventing unwanted mating is obviously a major part of the decision-making process. Behaviour is more of a mixed picture: castration might be very beneficial in some cases, but disappointing in some others. The owner might realise that the unwanted behaviour is either not testosterone related (so unaffected by castration), or even made worse following neutering. Moreover, the anaesthetic risk is never nil. As a result, a recent survey showed that 25 percent of pet owners were concerned or very concerned that neutering could be harmful for their dog (Mo Gannon and Associates, 2017).
All the observations above highlight the need for a discussion between vets and pet owners, in order to weigh up pros and cons but also manage expectations. Offering the option of a medical castration with a reversible effect can be extremely helpful in this dialogue. This achieves the same effect as surgery (sterility, same effect on behaviours, etc) but without the permanence, allowing both vets and owners to decide in due course what the best option is for the pet.