The BSAVA recommends that the neutering of companion animals should be considered for reasons of population control, prevention of unwanted litters and reduction of disease.

The decision as to whether to neuter an individual animal, for medical or behavioural reasons, needs to consider factors such as species, sex, breed and age of the animal as well as current and future health status. Veterinary advice should always be sought regarding the risks and benefits in individual cases.

There are several options regarding the timing and methods of neutering; owners and veterinary surgeons should discuss these options when making decisions for an individual animal.

Background information


The BSAVA strongly supports the practice of neutering cats – castration of males (tom cats) and ovariectomy or ovariohysterectomy (spaying) of females (queens) for the overriding reason of preventing unwanted kittens, thus removing the problems associated with finding homes or increasing the stray population.

Additional benefits of neutering cats include:

  • Reduction of roaming, and thus a potential reduction in numbers of cats injured or killed in road traffic accidents.
  • Reduction in fighting, and thus reduction in infected wounds and abscesses and spread of infection.
  • Elimination of the risks of pregnancy, and its complications as well as ovarian and uterine diseases.
  • Significant reduction in the risk of mammary tumours.
  • Neutering of cats is also likely to reduce the risk of urine spraying.
  • To prevent the perpetuation of genetic defects.

The BSAVA is a member of the Cat Group and supports the policy of pre-pubertal neutering (i.e at 4 months of age or older rather than at the traditional 6 months of age or older).

In some circumstances, neutering earlier than 4 months’ old may be deemed desirable, after careful assessment of the relative risks and benefits both to the cat and to the general management of the cat population. When neutering cats less than 8 weeks of age, sufficient and due regard should be made of the physiological immaturity of the cat.

Following neutering, animals can show increased food seeking and accumulation of body fat and thus neutering is known to be a risk factor for obesity. There is evidence (1) that fat deposition is increased in cats neutered earlier in life compared with cats neutered later in life. Thus, any decision to neuter should be combined with obesity prevention strategies such as monitoring and control of food intake.


The BSAVA recommends that neutering of dogs (castration of males and ovariectomy or ovariohysterectomy of females) should be considered in the following circumstances:

  •  For population control and to prevent the perpetuation of genetic defects.
  •  To prevent potential problems associated with the oestrus cycle (oestrus, season, or heat) and false pregnancy.
  •  For medical reasons, e.g. to prevent or remove testicular tumours, or reduce perianal adenoma or prostatic hyperplasia.
  •  To prevent or remove pyometra and other uterine diseases.
  •  To aid in the reduction of unwanted behaviours in male dogs, such as straying response to bitches in season.

There is evidence (2) that the effect of neutering on behaviour may vary amongst individual dogs.

The BSAVA does not have a specific view on pre-pubertal neutering in dogs. There is evidence (3) that the timing of neutering can influence the later development of a range of chronic conditions including urinary incontinence, neoplasia and orthopaedic conditions such as hip dysplasia and cruciate disease. Neutering is also a risk factor for obesity in dogs; early neutering is associated with a slight increase in growth rate, but the impact appears to be less marked than for cats. Nonetheless, obesity prevention strategies (such as monitoring of bodyweight and control of food intake) should always be implemented after neutering in dogs.

The BSAVA strongly supports the concept that a thorough benefit/risk assessment on an individual basis should be discussed with clients when deciding if and when to neuter individual dogs, incorporating both physical and behavioural considerations. If there are specific circumstances where neutering a dog less than 12 weeks of age is considered desirable, then sufficient and due regard should be paid to the physiological immaturity of the dog and, also, the specific breed.


The BSAVA recommends that all non-breeding rabbits should be neutered (ovario-hysterectomy and castration, respectively, for females and males) soon after they attain sexual maturity. The exact age varies with respect to breed, ranging from 4-6 months and up to 9 months in giant breeds.

Benefits of neutering include:

  • The prevention of pregnancy and unwanted litters.
  • The reduction of undesirable sexual mounting behaviour and hormonally related aggression.
  • The prevention of pseudo-pregnancy.
  • For medical reasons such as the prevention and treatment of uterine neoplasia and other uterine diseases.


The BSAVA recommends that, as a general principal, alternatives to surgical neutering should be recommended in ferrets, but that options and potential risks and benefits should be explained and discussed with owners to choose the best solution for the individual ferret and the owners’ particular situation and requirements.

Further information

The Cat Group

Berman E (1974) The time and pattern of eruption of the permanent teeth of the cat. Lab Anim Sci. 24(6):929-31.

Yates D (2019) Prepubertal neutering: a pragmatic approach. BSAVA Congress Proceedings. doi: 10.22233/9781910443699.17.3

Polson S, Yates D (2021) How to…Perform pre-pubertal neutering. BSAVA Companion. 2021(2): 16-23. doi: 10.22233/20412495.0221.16

References and further reading

(1) Nguyen PG, Dumon HJ, Siliart BS, Martin LJ, Sergheraert R, Biourge VC (2004) Effects of dietary fat and energy on body weight and composition after gonadectomy in cats. Am J Vet Res. 65(12):1708-13. doi:10.2460/ajvr.2004.65.1708. PMID: 15631038

(2) McGreevy PD, Wilson B, Starling MJ and Serpell JA (2018) Behavioural risks in male dogs with minimal lifetime exposure to gonadal hormones may complicate population-control benefits of desexing. PLoS One, 13 (5), e0196284.

(3) Urfer SR and Kaeberlein M (2019) Desexing Dogs: A Review of the Current Literature. Animals, 9(12), 1086.

Alexander LG, Salt C, Thomas G, Butterwick R (2011) Effects of neutering on food intake, body weight and body composition in growing female kittens. Br J Nutrition. 106 (S1): S19–S23. doi: 10.1017/S0007114511001851

Fettman MJ, Stanton CA, Banks LL, Hamar DW, Johnson DE, Hegstad RL, Johnston S. Effects of neutering on bodyweight, metabolic rate and glucose tolerance of domestic cats. Res Vet Sci. 1997 Mar-Apr;62(2):131-6. doi: 10.1016/s0034-5288(97)90134-x.

Salt C, Morris PJ, German AJ, Wilson D, Lund EM, Cole TJ, Butterwick RF (2017) Growth standard charts for monitoring bodyweight in dogs of different sizes. PLoS One. 12(9):e0182064. doi: 10.1371/journal.pone.0182064.

Vester BM, Sutter SM, Keel TL, et al. (2009) Ovariohysterectomy alters body composition and adipose and skeletal muscle gene expression in cats fed a high-protein or moderate-protein diet. Animal 3: 91287–91298. doi: 10.1017/S1751731109004868. PMID: 22444905.


Reviewed by members of BSAVA Scientific Committee (Alexander German, Jeremy Kirk, Caroline Kisielewicz, Lisa Morrow, Ian Self, Melissa Upjohn, James Warland) 2021

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