Vet with happy dog

When Should I Spay or Neuter my Dog?

When or if you should spay or neuter your dog is a popular topic which can cause disagreements between pet owners. It can cause confusion and anxiety when seeking advice, making the decision-making process harder.

In this blog, Kirsten Dillon, our Animal Behaviourist and Canine Specialist, shares her expert advice on the matter.

"Many vets will tell you to neuter early to avoid unwanted breeding and prevent certain cancers. While both are valid reasons to neuter early, there can be considerable fallout from neutering your dog too early. Neutering/Spaying them too early can impact your dog physically and behaviourally.

Research has shown that the removal of dog's sex hormones too early in their lives can impact their formation and growth—long-term implications, such as orthopaedic disorders, bone cancers and urinary incontinence. Furthermore, the larger your dog, the more impactful early neutering can usually be on their growth plates.

Removing these hormones too early can impact your dog's behaviour. Male dogs can lose confidence if testosterone decreases during adolescence, resulting in fear-related aggression. Female dogs have reported changes in behaviour, too; females are said to have shown higher human-related aggression incidents and early-onset urinary incontinence.

So, what is the answer?

After reading much of the available science on the subject, I recommend that female dogs be at least 18 months old and male dogs a minimum of 2 years old. These ages seem to balance behaviour challenges best with health benefits. Additionally, it is worth exploring alternatives to traditional surgeries, such as temporary castration implants in males (Suprelorin) and laparoscopic, ovary or uterus-sparing spays in females.

Finally, your dog's temperament, environment, early life experiences, and size should all factor into your decision. Behavioural issues are rarely rectified through neutering; science tells us it can sometimes exacerbate them. Training and behaviour modification are much more efficient alternatives to address unwanted behavioural problems."


By Kirsten Dillon,

Animal Behaviourist & Canine Specialist 



Hart, B. L., Farver, T. B., Oberbauer, A. M., McV. Messam, L. L., Willits, N., & Hart, L. A. (2013). Neutering Dogs: Effects on Joint Disorders and Cancers in Golden Retrievers. PLOS ONE, 8(2), e55937.

Kaufmann, C. A., Forndran, S., Stau-ber, C., Woerner, K., & Gansloßer, U. (2017). The social behaviour of neutered male dogs compared to intact dogs (Canis lupus familiaris): Video analyses, questionnaires and case studies. Vet Med Open J, 2(1), 22-37. Doi:10.17140/VMOJ-2-113

McKenzie, B. (2010). Evaluating the benefits and risks of neutering dogs and cats. CABI Reviews, (2010), 1-18. Doi: 10.1079/PAVSNNR20105045