Neutering (sterilising, castrating, spaying) - why and when

It is a sad truth that the number of kittens born every year is far greater than the number of good homes that can be found for them. As a result, thousands of healthy animals are destroyed and many more unwanted cats are left to fend for themselves. Having your cat neutered will not only help to reduce these numbers, it is also one of the simplest, safest and most practical ways of safeguarding your cat's health and welfare.

What does neutering involve?

Both castration in the male cat and spaying in the female are major operations which need a general anaesthetic. Your cat must be starved overnight before the operation to reduce the risk of problems on the operating table. However, there is very little chance of anything going wrong, it is one of the operations most frequently carried out by vets and any experienced vet will have done it many hundreds of times.

Both castration and spaying involve a single cut, into the belly of the female to remove the ovaries and uterus (womb), or into the scrotum of the male cat to take out the testicles. Your cat should be ready to come home on the same day as surgery, as soon as the anaesthetic has worn off. You may notice that the fur where it was shaved for its operation may re-grow slightly darker than the rest of its body but the contrast often disappears after the next time your cat moults its fur.

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What are the benefits of neutering?


Unless she is neutered a female cat will come into season three or four times a year and she could be having litters of kittens almost constantly throughout her life. Motherhood takes a lot out of a cat and having several litters is likely to shorten her life expectancy. The behaviour of a female cat in season changes varies markedly - she may appear nervous, she may either hide away or seek your constant attention. She will also advertise her availability to potential mates by spraying urine around the house and garden and she is likely to roll around on the floor on her back. Unless you want a female to have a litter of kittens she must be kept inside away from tomcats during each season. Neutering will stop the bleeding that occurs with every season and prevent these unwelcome changes in her behaviour.


Uncastrated tomcats will patrol a wide area in search of a mate and can detect a female in season over long distances. A tomcat who wanders is more likely to be involved in a car accident or become involved in fights with other males. This brings a risk of physical injury and infection with dangerous viruses such as Feline Immunodeficiency Virus which is mostly spread by biting. Tomcats also mark their territory - including parts of your house - with their urine. This has a powerful and extremely unpleasant smell which is often difficult to get rid of.

When should my cat be neutered?

Traditionally, female and male cats have usually been neutered at about six months old. Before the development of safe anaesthetics and surgical methods it was believed that a nearly fully grown animal would cope better with the operation. However, increasing numbers of vets now like to neuter animals much earlier, from about eight weeks. This eliminates the risk that a particularly advanced female cat may get pregnant before the operation. There is no evidence that such early neutering harms a cat's later health and physical development. Your vet will be happy to discuss with you the best time for neutering your cat.

Is it ever too late to have my cat neutered?

There is no upper age limit for neutering your cat. You may wish to have your cat neutered if you acquire it as an adult or you may want to have a litter or two before your cat is retired as a breeding animal. Tom cats can also be neutered later in life and this may reduce certain types of antisocial behaviour such as spraying. But the older the male is, the more likely that it will carry on showing the less desirable behaviour traits of a tomcat such as urine marking and fighting.

Is neutering dangerous?

All operations requiring a general anaesthetic involve a certain amount of risk and on rare occasions there may be complications after the operation. However, these dangers are far smaller than those that the cat is likely to run into if it stays sexually active.

Will neutering make my cat fat and lazy?

Neutering will not have any significant effect on your cat's lifestyle apart from eliminating its sexual behaviour. Because it is not wandering off in search of a mate your cat may need less food but you should be able to prevent it becoming overweight by giving it slightly smaller meals. Most owners find that any changes in their cat's personality are for the better as many neutered cats become more affectionate and playful.

Is it fair to let a female cat have just one litter of kittens?

It is an old wives' tale that a cat needs to have a litter of kittens. What your cat doesn't know it won't miss and neutering will save you the trouble and anxiety of finding good homes for the kittens.

Is neutering expensive?

Different vets may charge slightly different prices for a neutering operation depending on various factors such as the location, and the quality of the facilities at the practice. But all vets prefer to see as few unwanted kittens as possible and they try to minimise their charges. If money is short then you can shop around and people on income support may get help from one of the animal charities. However, it is wise to balance the costs of neutering against the expense of having an unwanted litter of kittens. A pregnant cat will need more food to support herself and her offspring, the kittens will need veterinary attention and you may have to advertise to find them good homes.

Related Factsheets:
Spraying - urine marking in the house
Breeding from your cat
Feline Immunodeficiency Virus (FIV)
Bringing home a kitten
Caring for your cat before and after surgery

If you want any other information on health issues concerning your cat please contact your veterinary surgeon who will be happy to advise you.