On November 6, 2011 an article was published on line that argues the negative health risks of spay and neuter procedures far outweigh the positive behaviour and health benefits, including decreasing dog overpopulation. In this regard, the author makes a further unsubstantiated claim that the dog overpopulation problem has been alleviated in the Lower Mainland of British Columbia. As the author does not cite the source of these claims, it is not possible to respond directly to the credibility of her information. However, an extensive Internet search of published and unpublished sources indicates that the likely source is Wikipedia.
Because the consequences of these claims could have a profound impact on our domestic animal population and those committed to caring for them, it is critical to consider the validity of these statements. The first point of contention is the claim that spayed females are more likely to develop human directed aggression than unspayed females. This statement is misleading. Peer reviewed research indicates that when this occurs, aggression existed in the female dogs prior to the spay and therefore, claims that spaying was the cause of increased aggression is false. More specifically, aggression (in all dogs) will naturally develop/worsen as the dog matures and reaches adolescence and thus is not caused by the spay procedure.
The risks of surgical complications are highlighted as a viable threat. However, the complications are minimal as evident in the relative routiness of the procedure and recovery time. There are risks to all surgical procedures and it is questionable why the author does not identify the risks inherent in the alternatives to spay and neutering provided. For example, tubal litigation and vasectomies are surgical procedures and would therefore pose inherent risks. It is more concerning, however, that the chemical alternatives the author suggests are currently more in the research phase and not practiced to any large extent in the pet population. This includes FDA approved Neutersol, an injection for males that, according to the author, “while nearly 100% effective [is] often very painful to dogs”. Suprelorelin, is not available in Canada and U.S. and while SpayVac is identified as an alternative, it is only currently used on wildlife and therefore, cannot be considered an alternative approach. An additional challenge with chemical alternatives is that they only prevent pregnancies and do not change hormonal levels/production. Consequently, they do not address the behaviour issues associated with intact males and unspayed females.
When an animal is spayed or neutered changes in their hormones may cause weight gain. Weight gain, however, is something that can be easily managed through a strict and healthy diet and adequate amounts of exercise. Given that animal guardians should be providing their pets with healthy food and exercise anyway, this affect of spay and neuter should not even be a point of consideration.
While there may be a statistical increase in cancer rates for some cases in spayed and neutered animals, it is more likely that the increase in incident rates is due to the fact that the animals are living longer, than it is directly related to their being spayed and neutered. Further, the cancers indicated are rare and thus any increase appears significant.
It is also argued that pet guardians can reduce the negative impacts of spay and neutering by waiting until their pet is over one year old. As there is no evidence provided in the article as to why this would be the case and there are no sources cited, it is not possible to speak to the credibility or validity of this statement. It is possible, however, to acknowledge sources that argue that waiting to neuter or spay your pet until they are older than one year and/or have experienced their first heat will likely exacerbate any existing behaviour problems, such as aggression and anxiety, as well as limit the effectiveness of preventing or diminishing certain health risks.
Finally, the article closes with an unsubstantiated claim that the dog overpopulation in the Lower Mainland has been alleviated. While there are no statistics provided to validate this claim, anecdotal evidence strongly suggests this to be untrue. Our no-kill shelters are beyond capacity, dogs are routinely euthanized at SPCA and municipal shelters throughout the province and local community based rescue groups are taxed beyond their means. It is irresponsible and dangerous to make such sweeping claims. Such claims against practices and procedures that have long proven to support a healthier canine (and feline) population undermine the work of animal health practitioners and animal welfare advocates who work tirelessly to reduce the numbers of unwanted, neglected and abused animals and promote spay and neutering as an important aspect of responsible pet guardianship. As veterinary medical research expands upon the knowledge and practice alternatives grow or shift with evidence, it is best to consult with your local veterinarian in regards to the options currently available in order to come to a consensus on the procedure that may be best for your pet.
Written in consultation with Shawn Llewellyn BSc, DVM