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This information is provided by Provet for educational purposes only.

You should seek the advice of your veterinarian if your pet is ill as only he or she can correctly advise on the diagnosis and recommend the treatment that is most appropriate for your pet.

Removal of the testes (castration, also called neutering, orchidectomy or gelding) is a common procedure in veterinary practice and is recommended for a wide range of species - but why ?

Castration is a relatively simple surgical procedure with few complications, but it is a major decision to take because it has important effects on the individual, including :

  • it prevents the individual from reproducing
  • it affects growth
  • it causes physical changes in the body 
  • it causes behavioural changes

In farm animals castration is carried out for several reasons :

  • to increase growth rate
  • to improve the quality of meat - meat from entire male animals (eg boars) often has a very strong, unpleasant  smell and taste
  • to reduce dangerous behavioural traits - for example, entire bulls can be dangerous to handle compared to neutered bullocks.
  • to prevent unwanted breeding - farmers only want to breed from the best genetic stock

In horses castration is carried out :

  • to prevent unwanted matings
  • to calm down their behaviour - entire stallions can be much more difficult to handle than geldings
  • for medical reasons - eg trauma to the testicles

In dogs castration is recommended for several reasons :

  • to prevent unwanted puppies
  • to modify antisocial behavioural traits such as :
    • aggression towards other dogs
    • mounting people
    • roaming
    • urine marking in houses
  • for medical reasons, including :
    • injuries to the testicles
    • cancer of the testicles - common in older dogs
    • torsion of the testicle
    • retained testicles (also called cryptorchidism or ectopic testes)
    • when there is a perineal hernia/rupture present
    • to treat prostate disease (hypertrophy or cancer) which are sex-hormone linked
    • to treat tumours around the anus (adenomas) which are sex-hormone linked

Cats are usually neutered to modify undesirable behaviour especially :

  • fighting other cats in the neighbourhood
  • to reduce the pungent smell of tom cat urine
  • to reduce spraying and territory marking in the home
  • to prevent unwanted kittens
  • for medical reasons - eg bite wounds involving the testicles

Rabbits and other small mammals are usually castrated to :

  • prevent unwanted offspring
  • prevent aggressive behaviour between individuals
  • for medical reasons eg trauma to the testicles

The decision to castrate an animal will depend to a large extent upon local environmental circumstances and if you have a male animal your veterinarian will advise you about whether or not you should have him neutered


Updated October 2013