For many dog owners, this isn’t really a question; in fact, for some, just asking is enough to incite the most basic, visceral responses. As a result of organized, modern movements from groups like ASPCA and HSUS to offer low-cost and in some cases forced sterilizations, a large part of the public automatically assumes that getting your domesticated companion sterilized is the morally correct choice. What does the research suggest though?
Research
According to research published in Canine Genetics and Epidemiology, the answer is not so simple. Of dogs that were sampled as part of the study, those that were altered showed a clear increase in risk for certain types of cancer along with an increase in the prevalence severe ligament damage. There is reason to believe this increase in risk for severe ligament damage is directly related to the decreased presence of sex hormones in altered dogs because these ligaments do have specific sex hormone receptors. Other research suggests “cognitive decline may be accelerated in the neutered state” along with ” a greater prevalence for immune disorders”(1).
Table 1. ref (1)
So does this mean choosing to get your dog fixed is the wrong choice? No. Research from other groups also suggests a decrease in negative behaviors, like mounting, roaming, urine marking and aggression when comparing altered dogs to their intact counterparts, although other research suggests there may not be a clear link(2). In addition to potential behavioral benefits, altered dogs obviously have less chance of disease associated with their altered reproductive organs.
Outside of simply removing reproductive organs; gonadectomy also causes a permanent change in levels of certain hormones. Simply put, concerning male dogs, when the testes are removed, the body no longer is able to control the level of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) which are normally controlled by a constant level of testosterone. LH levels remain permanently high in altered dogs and the effects of this permanently high level of LH are unknown(3).
Hunting Dogs
When it comes to answering whether or not you should have your hunting dog fixed, I would say it depends. When looking solely at health factors, it seems altering your dog potentially introduces some risk while reducing others. Research has also concluded that altered dogs, on average, do have a significantly (10-30%) longer lifespan. The other extremely important factor that is not captured in the reported literature is the variance of health factors across different breeds. Specifically, one could argue that the line breeding that has produced some of the most desirable hunting traits necessarily increases risk for certain health conditions that may not have been expressed in earlier generations.
Citations
(1)Belanger, J.M., Bellumori, T.P., Bannasch, D.L. et al. Correlation of neuter status and expression of heritable disorders. Canine Genet Epidemiol 4, 6 (2017). https://doi.org/10.1186/s40575-017-0044-6
(2)https://doi.org/10.1136/vr.140.24.617
(3)Front. Vet. Sci., 19 March 2021 | https://doi.org/10.3389/fvets.2021.603257
