Desexing (neutering) of male dogs is routinely recommended by veterinarians for all non-breeding male dogs. It is also recommended as a pet care management aid in treating some disorders in adult dogs.

Desexing a male dog involves castration - a surgical procedure performed under a general anaesthetic. Castration involves removing both testicles, thus reducing the quantity of male sex hormones in the animal. It is a permanent and irreversible procedure.

Whilst the male dog obviously does not carry a pregnancy, the involvement of the undesexed male dog in unwanted pregnancies is one important reason to consider desexing. There are many overcrowded animal shelters with many dogs being euthanased due to an oversupply of pets. Any procedure taken to reduce the number of unwanted animals in society is a positive step forward. Therefore all male dogs not intended as breeding sires should be considered for desexing.

Hypersexuality is an unpleasant trait seen in many male dogs, both desexed and undesexed. Hypersexuality is a complex of undesirable behaviours in male dogs, including but not limited to aggression, mounting other dogs/people or inanimate objects, marking their territory with inappropriate urination and roaming. Whilst hypersexuality can be attributed in part to the male sex hormones of the testes, the cerebral cortex in the brain is also involved. Hence desexing male dogs is used as an aid in reducing or controlling male hypersexuality in dogs but often needs to be used in conjunction with other treatments.

Prostatic disease is commonly seen in older male dogs. The prostate can be enlarged in a benign form or in a cancerous form. Prostate disease is primarily seen by owners as constipation in the male dog. Prostatic enlargement is stimulated by male sex hormones produced in the testes. Therefore desexing the male dog can greatly reduce the risk of this disease in later life. Male dogs who are desexed young are at a much lower risk of developing prostate disease than dogs desexed later in life. One of the procedures used to help relieve the symptoms of prostate disease in male dogs involves desexing, so in non-breeding stock early desexing is recommended.

Undesexed male dogs are also at increased risk of perineal herniation where abdominal contents protrude through a weakened portion of the peritoneum under the skin near the anus.

Testicular tumours can also be avoided by desexing male dogs.

Desexing of cryptorchid male dogs is highly recommended. A cryptorchid dog is a male in which one or both testes have not descended from within the abdominal cavity and into the scrotal sac/s. Dogs in which both testes fail to descend are infertile, but dogs where one teste has descended are still fertile as the descended teste usually retains normal function. It is recommended that cyrptorchid dogs not be used for breeding due to a suspected inherited hormonal abnormality involved in cryptorchidism. The risk of testicular tumour development in undescended testes is high, thus desexing of cryptorchid dogs is highly recommended.

Desexing a male dog has numerous long term pet health benefits. It is generally recommended that male dogs be desexed as puppies at approximately 6 months of age. Studies have shown that desexing male dogs at an age earlier than this provides many benefits so could be considered by owners in consultation with their veterinarian.

All owners of male dogs which are not intended for use as breeding stock should discuss desexing with their veterinarian. The benefits of desexing male dogs are numerous and studies have shown that desexing at an early age rather than as adults greatly enhance the expression of these benefits. Any adult male dog which has not yet been desexed or has is no longer used as a breeding sire should still be considered for desexing.