When Should You Neuter a Cat and Why: the risks and benefits

When should you neuter a cat, getting your cat spayed or castrated?  Are there any cat neutering side-effects with early neutering or is early age desexing the best thing you could do for your cat?


Benefits of spaying or castrating your cat

We castrate and spay our cats for many different reasons.  The big benefits to your cat (and us as their owners) are many:

  • Reduction in fighting. Cats are very territorial, even more so when sexually intact. This leads to increased fighting over resources, be that land, food or mates.

  • Elimination of pyometra risk. Pyometra is a life threatening infection of the uterus. Not many studies have looked at this in cats and so we tend to consider it in the same way we do with dogs. I have done a thorough review of the emergency pyometra here.

  • Reduced risk of FIV + FeLV. These are viral diseases that have no treatment and result in the early death of cats. There are vaccinations available but these are not 100%. They are often spread by fighting and the local risk varies by region. If you can reduce fighting you can reduce the risk of catching these diseases.

  • Reduced roaming and so getting lost or injured on the road. Looking for a mate can take your cat a long way from home. The further they go the higher the risk of having an accident becomes.

  • Reduced spraying and marking behavior. Entire cats are very territorial and will mark everywhere. Urine being sprayed in the house is unpleasant and scratching every surface in sight can cause a lot of damage.

  • Elimination of calling when a female is looking for a mate. This can be very noisy and disrupting and if you don't know what to expect it often causes a lot of emergency calls to the vet with people worried their pet is in a lot of pain. They cry loudly and roll around on the ground looking very distressed.

  • Reduction in general stress. Constantly looking over your shoulder for competitors or feeling you need to be continually marking your territory is a stressful business. your cat will be a lot more relaxed if you eliminate these behaviors.

Reduce unwanted kitten euthanasia

The other big benefit is a reduction in the number of kittens looking for new homes.  If there is one thing that cats are good at (and I believe they are good at lots of things!) it is getting pregnant and producing kittens.  Did you know that over half of cats admitted to animal shelters are kittens.

Now you might think that if your cat had kittens you would easily be able to find homes for them.  Unfortunately it is not always this simple.  I know how hard it can be as we often end up re-homing stray kittens at the vet clinic and it can sometimes take a really long time to find them homes even when they are incredibly cute and well behaved.

Cats can reach sexual maturity at 4 months old. Should they be neutered before this

This shows in the figures with over 40% of kittens coming from owned cats.  So that's 40% of all the kittens in shelters coming from the unintentional breeding of pet cats whose owners could not find them new homes.

As much as I would like to say that all these cats then found forever homes the reality is that around 30% of shelter cats are euthanized.  That is a huge proportion.

When should you neuter a cat?

The traditional age for a cat spay or castration is 5-6 months.  This is fine if it actually gets done then and your cat stays indoors until that point.  The age of sexual maturity though can be as young as 4 months of age.  This clearly leaves a window of opportunity for your cat to get pregnant if they are female, or start competing and fighting for the attention of any entire female in the neighborhood if your cat is male.

Why then not neuter your cat earlier?  Well, early age neutering is endorsed by many international organizations, including the British Small Animal Veterinary Association, and Australia’s Royal Society for the Prevention of Cruelty to Animals.  The American Veterinary Medical Association also currently recommends that cats not intended for breeding should be desexed before 5 months of age.

Ideally to reduce the euthanasia of healthy but unwanted kittens though we would be going a step further and castrating or spaying all cats before about 16 weeks of age, that is before they become sexually mature.

Cat neutering side effects + risks

But what are the potential cat neutering side effects of being spayed or castrated?  And does the age at which this takes place make any difference?

Well, concerns often voiced by veterinary staff include increased anesthetic risk, the development of low blood glucose which can be very dangerous and finally orthopedic problems.

Lets address these as well as some other problems people have suggested develop either after neutering in general or early age desexing.

Starting with anesthetic death, in several studies there is no difference in death rate with those undergoing this procedure from as early as 7 weeks to the those cats being anesthetized as adults.  Several different anesthetic techniques have also been looked at and all that were studied were found to be safe.

There is a risk with every anesthetic and surgical procedure but in reality this risk is very low at around 0.1% and the age at which a cat is neutered doesn't seem to affect this risk.  In fact, those cats neutered earlier actually seem to develop fewer minor surgical complications.

there are many benefits to being spayed or castrated but very few downsides or cat neutering side effects. Perhaps the only one being the risk of the surgery itself

Lets look at orthopedic or skeletal issues next.  We know in dogs that if they are neutered too early they may be at increase risk of developing joint issues.  It doesn't appear cats are the same.  for a start they very seldom develop cruciate ligament rupture and if they do it is generally because of a traumatic event.  The also rarely suffer from dysplasia, or abnormal development of their joints.

Something else that has been put forward is the fact that neutered animals may be more likely to suffer from broken bones.  Well the short answer is that this is not true in the studies that have looked into this.

It does seem that the growth plates stay open for longer in cats that are neutered but there is no evidence that this causes any health problems.

Next let's consider urinary tract disease and again there doesn't appear to be any association, certainly in male cats castrated early or later.  Older cats and those that are fat are a higher risk with castrated males living longer and tending to be more overweight (learn about obesity dangers here), but age at castration doesn't appear to play a role.

Finally, does early age desexing affect a cats behavior.  Well again, no. In one study those neutered earlier had increased hiding behavior but this wasn't found in a separate study and in both there was no difference in spraying, fearful behavior or aggression.

The bottom line is that it appears there are many benefits to being spayed or castrated but very few downsides of being neutered.  Perhaps the only one being the risk of the surgery itself.

The bottom line

As for when you should neuter a cat?  Well, I think it should definitely be done by 6 months of age and if your vet prefers to carry out the operation when your cat is 3 or 4 months old then that is absolutely fine.  There is no increase in risk at this age, they may actually experience fewer complications, and your cat will be guaranteed not to contribute to the global population of unwanted kittens.

As always with anything like this, you should discuss all of your options with your vet.  There may be other health considerations to consider before deciding on the best course of action in your particular cat and with any surgical procedure surgeon experience is a major consideration.

I hope this clears up the best age to neuter your cat or eases any concerns you might have had.  What are your thoughts?  Please leave me a comment below, I'd love to know when you think the best age to neuter a cat is.

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