Copyright 1993, 1994 Sarah Hartwell

This article was written in 1993 and I asked the major UK cat organisations (FAB and CPL) why they were not promotingearly neutering in the UK. At the time, FAB were cautiously interested in early neutering as a means of feral cat control, but CPL were opposed to early neutering. Veterinary association in the UK were also not generally supportive of early neutering and not receptive to the information available in the USA in favour of neutering below the traditional age of 6 months. An updated article reflecting the changing situation in 2008 is at Early Neutering - Increasining Acceptance

In a veterinary clinic in America or Australia, a responsible owner takes her two new cats to be neutered. They are booked in and taken to pre-surgical waiting area. The neutering is straightforward and uncomplicated and the two recover quickly in the post-operative ward. By the time the owner collects them, they are playing. When the owner returns that evening, the female has been "kitten-proofed" while the male will not be fathering any offspring. The owner need not worry about her pets adding any accidental or unwanted offspring to the already vast cat population in an area where fewer than half of all unwanted cats find new homes. In her cats' cases, however, there is something rather unusual by British standards - they are only 12 weeks old.

For many years, British cats have been neutered between 5 and 6 months of age, at the onset of puberty. Some vets delay neutering even later if the cat is not showing signs of sexual maturity. A few operate on early maturing cats, e.g. at 4 months. Most are unwilling the neuter cats under 16 weeks of age. However, better nutrition means that cats are growing faster and maturing earlier. Some females are already pregnant at months old while some males may already have fathered kittens, in some cases as early as 4 months old. American animal shelters found, to their distress, that some people who adopted kittens either failed to have them neutered (despite signing a point-of-adoption neutering agreement) while others adhered to the mistaken belief that a female should have a litter of kittens before being spayed. Despite there not being enough homes to go round, people were still allowing their cats to breed.


Shelter workers began to feel that they were homing kittens only to see the offspring of those kittens brought into to the shelter a few months later because people had failed to abide by neutering agreements. The same is found in British animal shelters where owners arrived with kittens telling shelters that they were obliged to take the kittens because the mother had been obtained from that shelter. In a few cases, shelters had unknowingly rehomed a young cat which was in the early stages of pregnancy. In a small number of cases the cat matured precociously and was pregnant when presented for spaying; many owners will not have cats aborted and some dislike performing abortions, especially late-stage abortions, unless medically necessary to save the mother cat's life. In the majority of cases the problem was due to owners failing to neuter the cat at 6 months of age.

Neutering agreements are notoriously difficult to enforce should owners renege, move house or 'lose' the cat. Whether such agreements are legally binding is unclear since no cases have come to court in the UK. Even if the owner intends to honour the agreement, some cats can (and do) breed before reaching 'neutering age'. Some owners insist that females need one litter first and allow cats to become pregnant 'accidentally' at 6 months.

Some adopters agree to have the cat neutered when they have no intention of doing so and other owners acquire cats from sources which don't require neutering and which don't do post-adoption checks. One prospective owner faced with a neutering agreement attacked rescue shelter neutering policies, exclaiming "They need to have a litter first - you're the experts, you ought to know that!" Another arrived to reclaim her straying cat (non-pedigree) and threatened to sue the shelter for spaying it against the owner's wishes; in fact the cat had been found in a garden one night and had received an emergency, life-saving, hysterectomy around midnight after its pregnancy had gone disastrously wrong (it was not even close to full-term). The owner refused to take her cat back purely because it had been spayed.

In the US, it was estimated that up to 50% of adoptors failed to have cats neutered in accordance with neutering agreements (and this in a litigation-happy society!). Adopters preferred to adopt cats which had already been neutered.

Bodies governing pedigree cats may be able to bring more pressure to bear on owners who fail to comply with neutering agreements; rescue societies deal with a vast number of cats, on tight budgets, and face a far harder task trying to enforce such agreements. 90% of pet cats are non-pedigree.

Some shelters in the US decided that this situation needed to be prevented in order to reduce the huge numbers of cats euthanased annually in many American animal shelters. They also realised that most prospective cat owners preferred to adopt cats which had already been neutered. To this end, they took the step of neutering kittens before rehoming them.

This policy has paid dividends in areas where it has been adopted. One Society For the Prevention of Cruelty to Animals (SPCA) in Boston reported a 68% decrease in the number of animals euthanased since the introduction of early neutering. The success of their new approach to population control and adoption is such that other shelters are taking the idea on board. Southern Oregon Human Society has been running an early-spaying scheme for 19 years. Memphis Animal Control Shelter conducted a 3 month pilot program in 1987; the pilot program was deemed a success. Such shelters feel that they are "taking away a problem before the pet owner has one." Those problems would otherwise fill up cat shelter cages.


The aim of early neutering is to prevent problems from being born and reduce the number of cats which have to be euthanased because they are unwanted. Birth control (birth prevention) is preferable to population control (the killing of healthy cats).

Early neutering has also proved invaluable to humane societies specialising in humane control of feral cats. Untameable feral kittens could be neutered and immediately returned to their colony instead of being euthanased or kept penned until they reached 6 months of age. Not only could kittens be returned immediately to familiar territory, they did not have to contend with the problems endured by unneutered ferals (continual breeding, fighting and increased risk of passing infection through bite wounds). The neutered male kittens can grow up as neuters (i.e. relatively non-competitive) rather than contending with suddenly changed status or bullying by unneutered males if they are neutered in adulthood.

Young ferals kept caged until 'neutering age' risk losing their place in the colony or have problems settling into a territory they have largely forgotten. Perhaps they should be released and re-trapped when they reach the magical age? Re-trapping them later may prove impossible - they may have moved elsewhere or be trap-shy. Cat shelters are faced with the problem of accommodating these cats until they reach the magical neutering age. In order to accommodate them until that age, other cats (including pets) must be turned away because there is 'no room at the inn'. Those turned away face uncertain futures or euthanasia while the ferals themselves do not relish a long stay in even the most luxurious cattery and are an additional drain on shelter resources.


Vets in the UK have widely differing opinions about early age neutering and veterinary associations appear unwilling to accept information from studies performed in the US. (To further illustrate the problem of inconsistency among vets, one feral carer was informed by her vet that a nursing feral female on her land could not be spayed until her kittens were 12 weeks old - by which time the mother was pregnant again and the vet refused to perform an abortion. The owner had no way of confining the cat who seemed condemned to perpetual motherhood until an alternative vet performed the spaying.)

Although not yet the "norm", early neutering is becoming more widely accepted in the US as one way of controlling the cat population. It may also be introduced into cat control legislation in parts of Australia where strict cat-ownership laws are being introduced in a bid to protect native wildlife. For instance, some Australian legislators propose to make it illegal to sell or rehome a kitten which has not been neutered (except pedigree kittens needed in breeding programs) and the proposed registration fee for an unneutered cat may be as much as forty times that for a neutered cat.

In Britain there are still reservations about early neutering, although a number of vets are willing to neuter kittens at 8-12 weeks old, particularly if the kittens are feral and being returned to their colony. One vet reported having practised early neutering since 1971 with no detrimental effects. Another vet neutered over 600 kittens aged between 8 and 20 weeks in 1988-89 and again reported no adverse effects. Other vets are still firmly opposed to the practice despite the success of long-established early-neutering policies in the US and one or two places in the UK.

It has long been held that bitches should not be neutered until after their first season and this belief may have been extended to cats. For many years there were few feline specialist vets so cats were treated as though they were small dogs. This means a tenacious tradition of not neutering before 6 months of age. Older barbiturate anaesthetics presented a real barrier to performing operations of any kind on kittens or immature cats. Modern anaesthetic drugs have been found to be much safer for very young or very old animals. The training of vets and veterinary anaesthetists has also improved over the years as knowledge about cats has increased, making operations on kittens feasible.

One veterinarian told me that kittens should only undergo such major operations in life or death situations. Due to overpopulation and rates of euthanasia of healthy cats, this is a life or death situation, particularly for untameable feral kittens. In the case of ferals which is more cruel: early neutering and return to site, destruction or expensive incarceration for around 3 months? Thousands of healthy but unwanted cats are destroyed annually in Britain; early neutering is a potentially useful tool for reducing these figures.

No surgical procedure, on an animal of any age or size, is completely without risk. A spotless operating room is essential when neutering kittens. It is unsafe to neuter sickly kittens because of infection/stress. There will always be a few cats, adults and kittens, at high risk from surgery. This is outweighed by current euthanasia rates due to feline overpopulation. Early neutering is not a cure-all, but it isn't barbaric and it is a useful weapon against overpopulation and irresponsible refuse-to-neuter owners.

What are the main risks associated with early age neutering. Many of the risks are the same as those associated with any early age surgery. It poses a few potential anaesthetic problems because kittens have greater oxygen consumption than adults and there is a greater risk of hypothermia during anaesthesia because of a kittens small size (though vets regularly and successfully operate on a variety of comparably sized small pets). There is therefore a need to carefully monitor a kitten's body temperature, breathing and heart rate. There is greater difficulty of intubation due to the smaller size and less rigid structure of kitten's tracheal cartilage.

Anesthetic complication rates following early age altering reported in the literature are very low. One study of 96 kittens reported no complications. A survey of kittens altered by fourth year students for humane organizations at Texas A&M University found that early age spay/neuter did not increase morbidity (illness) or mortality (death) during the intra- or postoperative period (7 days after surgery). Kittens neutered at less than 12 weeks of age actually had a lower postoperative complication rate (6.5%) than those neutered at greater than 23 weeks of age (10.8%).

Practical guidelines given to American vets are: Ensure that the kittens have a complete physical exam prior to surgery; ideally, they should be vaccinated and treated for parasites several days before surgery (this is not always possible in a cat rescue situation). Surgery should be postpone if any abnormalities are found (e.g cryptorchidism). Each kitten must be weighed accurately (to the nearest 100g) to calculate drug doses. Combat hypoglycemia by withholding food for only 3-4 hours before surgery and feed a small meal within 1 hour of recovery from the anaesthetic.

Before surgery, keep kittens (with their littermates if possible) in a warm, quiet environment to decrease excitement and stress. Keep handling to aminimum so they don't get excited and use intra-muscular injections rather than intra-venous injections since IV can be excessively fiddly due to the small veins and the kitten may get stressed and need to be restrained more.

Kittens who take longer to recover or who will not eat after recovery should be given 50% dextrose solution orally. Hypothermia must be combated during induction (being given anaesthesia) and surgery. Keep fur clipping to a minimum. Avoid use of alcohol in surgical preps and warm surgical prep solutions. Check the kitten's rectal temperature at the end of the surgery. Continue to keep the kitten warm after surgery and during recovery.

Operating on a small animal is always fiddly. In male kittens the testicles may be undescended. In female kittens, the spaying incision is larger in proportion to size and the tissues more fragile, however, there is less fat in the abdomen. It may be preferable to do a midline (abdominal spay in kittens than the traditional British flank incision). Operations on cats of any age carry a degree of risk, but a good vet and anaesthetist can overcome these additional concerns when operating on kittens.


A neutered kitten's growth is not stunted, although males do not develop the characteristic tomcat "jowls". In a parallel scheme for dogs, early-neutered puppies were found to become "leggier" adults than those neutered at the more usual age as the sex hormones appear to affect the 'switching off' of bone growth. Though no data has been collected, the same may be true of early-neutered kittens. Fears about stunted growth are unfounded. Legginess and the absence of tomcat jowls is only of concern to exhibitors (breed standards should make provision for neutered cats having a slightly different appearance).

It is hard to assess whether earlier neutering has any additional positive effects on behaviour (other than preventing sex-related behaviours), but no adverse behavioural effects have been noted.

One reason given for delaying the neutering of males until 6 months is to allow the urinary system to become fully grown. Neutered males may be more prone to urinary tract blockages, especially if fed mainly dry cat food. However, advances in cat food formulation to control the acidity of the urine appear to have eliminated this problem. The nutritional needs of early neutered kittens appear to be no different to those of unneutered kittens and it does not necessarily follow that a neutered cat or kitten grows fat and lazy. Neutered adults apparently need fewer calories than unneutered adults but overweight and laziness, often cited as inevitable side-effects of neutering, are most usually due to overfeeding and boredom.


It appears to be tradition which dictates neutering age. Perhaps in the light of cat numbers, modern anaesthetic/surgical techniques, and improvements cat food formulations, the customary neutering age needs to be re-assessed in the UK. To compound the current problem, there is a major problem of some low-cost neutering clinics apparently only performing castrations; a policy which is short-sighted as kittens need to be prevented at source i.e. through spaying the females.

Although there are those who find the thought of neutering kittens abhorrent or even barbaric, it's worth remembering that some alternatives are even more abhorrent - euthanasia of healthy unwanted cats and regular culling of ferals. Cat workers are painfully aware that neutering contracts can be notoriously hard to enforce; even the most obliging adopter may have moved house, lost the cat or found their cat unexpectedly (or deliberately) pregnant when the time arrives.


One drawback for cat rescuers is the added cost of having kittens neutered before adoption and it may take some years before cat-workers reap the benefits of having fewer kittens or pregnant cats come into care. Long term early neutering policies have proven successful abroad and both cat owners and cat workers (especially those dealing with feral cats) may wish to discuss the possibility of early neutering with their own vets.

Finally, there needs to be some way of identifying pet female cats which have been spayed (at whatever age) so that they do not undergo a second, unnecessary operation should they be found as strays. Almost all cat-workers have encountered this problem. Ear-tipping is the recommended method for identifying neutered ferals but is unsightly and unsuitable for owners. Ear-tipping is obviously not acceptable in the world of pedigree cats. Microchipping is the most obvious solution, with the cats neutered/unneutered status being recorded on the microchip manufacturer's database.

Some feral carers avoid ear-tipping feral cats as it makes them instantly recognisable as unowned cats and a target for cat-haters. Mass microchipping is expensive. Tattooing is one option, though tattoos fade over time and are also not visible on dark coloured cats. Freeze-marking (e.g. inside the thigh) while still under anaesthetic could be used to identify neutered and spayed ferals.