From around the age of 4 months, kittens reach sexual maturity and are therefore capable of breeding and producing kittens themselves.
Most people do not have the time or desire to breed from their cat and do not wish to add to the number of unwanted cats and kittens already looking for homes. Neutering a cat – castration in the male (removal of the testes), and spaying the female (removal of the ovaries and uterus) – not only prevents unwanted pregnancies occurring, but also curbs unwanted behavioural patterns associated with sexual maturity and reduces the risk of certain diseases.
In the past it has been suggested that all female cats should be allowed to have one litter of kittens. However, this is totally unnecessary and of no benefit whatsoever to the cat. It is therefore preferable to have a female spayed before she reaches sexual maturity. Once sexual maturity is reached, the cat will begin to come into season or 'call'. Cycles of sexual activity typically occur every two to three weeks, and when a cat is 'calling', as its name implies, this can be a very noisy affair!
Population control. It is important to neuter a female cat before she can have kittens herself. This happens very quickly depending on breed, time of year born and individual development. The first season usually occurs around six months but can be earlier. Queens can have up to three litters in a year.
Control of nuisance. Female cats will ‘call' (come into season and be receptive to the male cat) regularly, about every three weeks during sexually active times of the year if they do not get pregnant. Having entire female cats in an area will attract entire males with the attendant problems of spraying, fighting and caterwauling.
Welfare issues. Unwanted kittens may not be cared for and are likely to suffer from various infectious diseases such as cat 'flu or worse. There are unlikely to be enough new homes available for them.
Health issues. Female cats which are not neutered are more likely to suffer from pyometra (infection of the womb) later in life and with mammary tumours. Queens with infectious diseases may pass these on to their kittens. Pregnancy and birth are also not without risk.
Wildlife issues. Cats with kittens will hunt more actively and if they are not being fed will need to catch more wildlife to feed their kittens.
Castrating a male is equally important as spaying a female to prevent unwanted pregnancies. Furthermore, entire male cats have a strong tendency to roam, to be aggressive to other males, to fight and to mark their territory by spraying urine (often indoors!). The aggressive behaviour puts an uncastrated male at much higher risk of serious infectious disease such as feline immunodeficiency virus (feline 'AIDS') and feline leukaemia virus, both of which are transmitted through cat bites.
Castration involves removing both testes under general anaesthetic through a small incisions into the scrotum. As with the spay operation, withholding food from the previous evening will be required to minimise potential anaesthetic complications, and the kitten can usually go home the same day. Usually the skin incisions for a castration are so small that sutures are not required.
Unneutered male cats are likely to stray over a large area, will mark their territory with a very pungent spray and are much more likely to fight - with attendant noise nuisance.
Fighting males are much more likely to spread diseases such as FIV and FeLV to other cats. They are also likely to suffer from fight injuries such as abscesses. Because they wander over a large area they are also at greater risk of suffering road traffic accidents.
Unneutered male cats will wander from home and may not return. They may also spray inside the home and may be aggressive to their owners. Therefore it is desirable to neuter kittens early enough to ensure that the above problems are prevented. Most people do not want to live with an unneutered male cat.
Obviously male cats do not have kittens themselves and it only takes one male in an area to make lots of female cats pregnant, so neutering a female cat makes a great deal more difference to limiting numbers, but it all helps!
Millions of pet lives are tragically lost due to diseases and overpopulation, by spaying and neutering your pets, you can contribute greatly to the solution.