Deciding when to spay a dog

Updated 02/11/2023

Pet parents settling into life with a fur baby by your side, have you considered what will happen when your pup’s all grown up? Unless you’re planning to add to your furry family, you’ve likely thought about spaying your four-pawed pal. We’ve dug up some dirt on the subject to find out the answer to “When should you spay a dog?”, and sniffed out the pros and cons of doing so. But before we go barking up the wrong tree, what is spaying? 

Spaying involves removing a female dog’s reproductive organs (the ovaries, fallopian tubes, and uterus) so she is unable to have puppies. This is different from castration, in which a male dog’s testicles are surgically removed. Now, before we take a look at when to spay a dog, let’s find out why you should (or shouldn’t) do it in the first place.

The benefits of spaying dogs

• To put it simply, spaying your four-pawed pal reduces the number of unwanted puppies. We know, how could anyone not want a puppy?! Unfortunately, thousands of puppies are abandoned every year, putting a huge strain on the animal shelters that rescue them and leading to a small number of them being euthanized.  
• Spaying a dog also reduces the risk of certain illnesses, including mammary cancer and urinary incontinence. As a result of this, spaying is thought to increase a dog’s lifespan.
• Spaying is cost-effective, as it reduces the chance of vet bills due to illness.  
• Finally, spayed dogs don’t go into heat, which means they won’t bleed from the vulva or experience the behavioral changes associated with the reproductive cycle.

The downsides of spaying dogs 

• As with any surgery, the procedure comes with risks such as surgical complications and reactions to the anesthetic.
• Spaying can reduce a dog’s resting metabolic rate, meaning that your four-pawed pal may gain weight if their food portions aren’t reduced.
• Spaying dogs before they reach maturity may increase the risk of certain health conditions, which is why it’s so important to know when to get a dog spayed.

When to spay a dog

Until recently, it was common practice to spay and neuter dogs at four to six months of age. It was understood that the earlier the dog was spayed, the easier the surgery was for both the vet and the puppy.

However, research now suggests there are benefits to waiting a little longer, especially with large breed dogs. In a study undertaken by researchers at the University of California, Davis, it was found that spaying certain breeds at such a young age could have serious health consequences. Of the 35 dog breeds that were examined, spaying large breeds at a young age was found to increase their chance of developing joint disorders such as hip dysplasia, whereas there was little evidence to suggest that it had an effect on the health of smaller dog breeds. 

So when is the best time to spay a dog? The general recommendation nowadays is to spay dogs once they reach adulthood, but as this varies from breed to breed, it can be hard to pinpoint the perfect moment. Speaking to your vet to find out when your dog will stop growing and assess their risk of disease is the surest way to determine what age to spay or neuter your dog. 

When to spay a small dog 

Small breeds weighing under 45 pounds can reach sexual maturity as early as six months old, which means it’s generally safe to spay them around this time. 

When to spay a large breed dog 

According to the Davis study, the health problems associated with spaying dogs at a young age mainly affected large and giant breeds. For this reason, it’s important to wait until large breed dogs are fully mature before getting them spayed, which might not be until 12-18 months of age. 

When to get a female dog spayed 

Female dogs should be spayed once they reach maturity. Spaying a dog in heat should never be attempted unless there is a medical reason as the surgery can be more complicated, and pet owners are usually advised to wait at least three months after the heat cycle has finished to give the blood vessels and tissues time to return to normal. 

When to get a male dog neutered

Just like female dogs, male dogs should be neutered once they reach sexual maturity. Signs your good boy is all grown up include lifting a leg to pee and showing an interest in females in heat. 

As you can see, there’s no “one size fits all” in the world of dog spaying. Knowing when to spay a dog varies greatly depending on breed, size, health, and lifestyle, so it’s best to speak to your vet before determining the right time for the procedure.    

Meet our veterinary expert, Emma

This article has been checked by veterinarian Emma Chandley, BVetMed MRCVS PGCertSAS. Emma graduated from the Royal Vet College in London in 2011. She has a keen interest in surgery and went on to do a postgraduate certificate in small animal surgery and was then awarded advanced practitioner status in the same discipline.