Are there any pros to early neutering? by Steve Dean
At the recent British Small Animal Veterinary Congress one of the contentious issues was the subject of early neutering. Neutering dogs (and cats) at an early age, often as early as three to four months old, has become increasingly popular. However, several concerns have been raised about the potential ill effects arising from neutering a dog before it is mature. A recent effort to review the incidence of urinary incontinence, often thought to be more common in the spayed bitch, failed to prove a link with neutering despite finding plenty of published information but equally, the review, failed to dispel the theory either.
An RSPCA vet made a good case for neutering rescue dogs at an early stage. His argument was straightforward – because a charity often has only one opportunity to intervene and influence a dog’s future life, it makes sense to act when the dog is in their care. Evidently, many of their rehomed dogs do not return for further treatment and even if the new owner leaves with a voucher for neutering at a later stage they often do not use it.
Less impressive was the constant reference to lower cost being a significant reason for early neutering. It would be more digestible to hear a charity would be concerned to choose the time to neuter in the best interests of the dog and not because it improved the balance sheet. Nevertheless, it is worth noting that the RSPCA deals largely with dog owners who are the least likely to consult a vet or take a responsible attitude to an unwanted pregnancy. Thus this does influence their attitude towards early neutering schemes.
By way of contrast, it was refreshing to hear that the RSPCA recognises there is a lack of data to support early neutering. However, the charity still argues for early neutering mainly believing this contributes to reducing the stray or abandoned dog population. A further justification for early neutering is a lower likelihood of surgical complications in a young bitch. All this may be sensible for the rescue dog, but is this a sensible justification for the general practitioner to use?
The concept that neutering reduces the number of dogs requiring rehoming was strongly challenged by an Australian veterinary surgeon. She was a strong advocate of better education about dogs and their care. Her reasoning suggested how neutering was used more for the convenience of the owner and its intent is to make the dog more acceptable to live with. However it appears there may be an argument for not neutering based upon its affects on canine behaviour.
Assuming the public has unreasonable expectations of the relationship with their dog, surveys have revealed how poor behaviour is cited as a major reason for rehoming or euthanasia. In particular, barking and boisterousness are major reasons quoted for parting with a dog. Since most puppies often do both extremely well this is worrying. Furthermore, the public has a poor understanding of characteristic breed behaviour.
The genetic basis of behaviour is well established. However, in terms of neutering, removal of the reproductive organs at an early stage may coincide with a period of development when a maturing puppy is highly socially sensitive. Such periods are associated with changes in mental chemistry and it was argued this is not the right time to neuter and thus derange the normal hormonal changes expected around this time.
Veterinary surgeons often recommend neutering for aggression yet only about a third of aggressive dogs respond positively. Add to this the probability of greater cognitive impairment in older neutered dogs and this raises the question of why neuter dogs at all? This alone could be considered controversial yet a cancer specialist went on to state how early neutering in some breeds could increase the risk of bone cancer.
It is well known that early neutering delays the closure of growth plates in the long bones and in large breeds, already prone to developing osteosarcoma, this increased period of growth may double or triple the risk of bone cancer development. Further evidence suggests an increase in prostatic adenocarcinomas associated with early castration. In bitches it is generally accepted that neutering reduces the incidence of mammary cancer but in neutered bitches mammary tumours are more likely to be malignant.
The big surprise, however, was the revelation relating to the assumed benefit of early neutering in respect of the reduction in mammary cancer. It apparently is based on some dubious science. Vets have been educated to believe that spaying a bitch before her first season produces a dramatic reduction in the incidence of mammary tumours but it appears the data supporting this is very weak.
The last of the quartet of veterinary speakers dealt with incontinence, which is frequently associated with neutered bitches. It is however difficult to prove this link whereas obesity has a much clearer association. Lack of development of the vulva is also associated with neutered bitches but this expert’s view was obesity was more significant here, too. However, the accepted association between spaying and obesity does have to be taken account of.
Yet one issue was clear. Where an individual bitch suffers from juvenile vaginitis, it is more difficult to resolve if the bitch is neutered before her first season. In contrast it is worth noting how the condition often resolves if the affected bitch has a season. A case was made therefore for at least delaying the neutering of high risk breeds or dogs with specific diseases? Those breeds that suffer a high incidence of bone cancer are clearly logical candidates and indeed in some breeds it may be better not to neuter at all.
Returning to mammary cancer, the oncologist confirmed how little we know about the true incidence in entire bitches but added evidence to suggest removal of small growths at an early stage significantly reduces the risk of these tumours becoming malignant. Thus suggesting a timely, early surgical removal of small mammary tumours could be as effective as routine early neutering
Even in male dogs, in the lower urinary tract, transitional cell carcinoma is more common in neutered males and prostatic cancer, which is also seen in castrated dogs, is not currently a survivable cancer. At the end of the debate there was growing support for a more considered approach to neutering although nearly everybody understood why rescue dogs might be neutered routinely. However, even here, there are arguments that suggest public education might be more effective in reducing the numbers of unwanted dogs.