Surgical desexing or sterilisation involves the removal of part of the reproductive system of pets whilst under a general anaesthetic.
Veterinarians recommend desexing to prevent unwanted litters of puppies and kittens. In female dogs, desexing automatically stops their cycles and the associated bleeding and attention from male dogs. Castration helps to control male dominance aggression problems and also reduces their wandering instincts if a bitch in the neighbourhood is on heat. Uncastrated tomcats have a tendency to roam and fight, leading to cat bite abscesses.
There are also significant medical reasons for desexing. Spaying performed before two years of age reduces the risk of mammary tumours (which are very invasive). Tumours of the ovaries, uterus and cervix, and pyometra (a gross infection of the uterus) can be prevented. Castration reduces the risk of prostatic disease, perianal tumours, and eliminates the risk of testicular cancers.
Desexing may also be recommended in your pet to prevent hereditary diseases being passed on, or for treatment of some diseases such as prostatic hypertrophy or pyometra.