Castration and spaying for your pet, as well as advice on when and why to perform them.


Neutering is an operation carried out by a veterinary surgeon to remove the reproductive organs in pets, referred to as castration in males and spaying in females.

It stops your pet from reproducing, and also can help to prevent some serious illnesses, including associated cancers.

Below are some of the benefits you could see from neutering your dog, cat or rabbit, for both males and females.

Neutering your male dog

Castration is the removal of testicles from male patients. From a health point of view, it can have many benefits for your dog.

It eliminates the risk of testicular tumours, and reduces the threat of prostatic disease and of hernias developing later in life.

It will also help with undesirable behaviours such as tendences to escape, roam and fight other dogs, as well as sexual behaviours including indoor urine marking and discharges. However, it will not calm your dog down or change any other non-related behaviour issues.

You should consult with your vet on when to have your dog castrated, but generally we recommend that small dogs have the operation between six and 12 months, medium dogs at 12 months, and larger dogs between 12 and 18 months.

Neutering your female dog

Spaying is the removal of the ovaries and/or uterus from female patients, and also has a range of health and behavioural benefits.

It eliminates the risk or pregnancy and phantom pregnancy, serious womb infections called pyometra, and ovarian and uterine cancers. Breast cancer instances can also be reduced, or even eliminated.

It also means that your dog will not come into season, also known as heat, in which it will attract the attention of male dogs and may see changes in behaviour.

You may choose to have your dog spayed before their first season, in order to avoid the issues above. However, neutering before the first season may increase the risk of urinary incontinence later in life and of joint problems in larger breeds.

Because of this we recommend that small breeds of dog have the operation between six and 12 months, and all other dogs after their first season, at nine to 12 months for medium breeds, 12 months for large breeds and between 12 and 18 months for particularly large dogs. We will honour requests to perform the operation before a dog’s first season, but please speak to your vet to discuss this.

It is not recommended to spay dogs during heat, or for 12 weeks after they have been in season.

Neutering your male cat

We recommend castrating cats at four months, at which stage they will be capable of breeding – even with siblings and parents.

As with dogs, neutering cats has a range of health and behavioural benefits.

It reduces your cat’s desire to roam and to fight with other cats. This in turn means they are less likely to go missing, be hit by cars and have less chance of contracting feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) which are transmitted by cat bites and reproductive activity.

It will also reduce aggressive behaviour associated with testosterone in your cat, as well as stopping your cat from spraying urine to mark territory, and making urine smell less strong.

Neutering your female cat

As with male cats, females can breed from four months, and should be spayed before this.

Female cats can eliminate similar health concerns to female dogs through spaying, including cancer of the womb or ovaries and pyometra, a potentially life-threatening womb infection.

It also means that your cat will not come into season, which can cause behavioural changes and stress for your cat. If a female cat is in heat, unneutered male cats will be attracted to your property, with associated problems such as urine spraying and fighting.

Neutering rabbits

It is important for rabbits’ happiness that they live in pairs or groups, otherwise they can become lonely.

However, if they are not neutered, they can develop aggressive, territorial behaviour connected to their hormones. Furthermore, if male and female rabbits live together they will produce litters.

Spaying female rabbits also stops them from developing cancer of the uterus – up to 80% of un-neutered females develop cancer of this kind.

Female rabbits should be neutered at around 16 weeks, as long as they are healthy and weigh at least 1kg, while male rabbits should be castrated at around 12 weeks, once their testicles have descended.

© 2020 VetPartners Practices Limited t/a Caerphilly Veterinary Clinic

Registered Address Leeman House, Station Park Road, Holgate Park Drive, York, YO26 4GB

Company No. 07357355 Vat No 228 9288 65

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