There are many reasons for spaying a female dog or castrating a male dog other than preventing unwanted puppies. Neutered dogs tend to be healthier than fully intact dogs because they are not subjected to the hormone surges that can trigger some canine illnesses. Removing organs that usually become diseased in your dog's older years can also help prolong your dog's life.
Prevention in Females
Dogs have 10 breasts. The most common type of tumor in canines is breast or mammary gland tumors, especially in females. Twenty-six percent of unspayed female dogs will get a tumor by the time they are 10 years old. Forty-five percent of these tumors will be cancerous. Female dogs that are spayed before their first heat have a 99 percent chance of never developing breast tumors, according to "Dog Owner's Home Veterinary Handbook."
Prevention in Males
Testosterone gradually enlarges the prostate gland of a male dog. When the dog is at least 5 years old, the enlarged prostate starts to cause health problems. A dog with an enlarged prostate has problems urinating and defecating, as well as blood in the urine. Neutered males also have fewer anal tumors and discharge from the penis, according to Mar Vista Animal Medical Center.
Male and female dogs are prone to cancers of the reproductive organs. When these are removed through spaying or neutering, the chances of the dog developing specific cancers, which include ovarian, vaginal and testicular cancers, is eliminated.
Unspayed female dogs are prone to developing infections in their uterus called pyometra, which means "pus womb" in Latin. This infection causes the uterus to fill up with pus-filled cysts and can kill the dog. Usually, the treatment for a dog with pyometra is to spay her. Pyometra is caused by surges in hormones estrogen and progesterone, according to Mary Smith, DVM.
Although neutering does reduce many prostate problems in dogs, it does not stop the development of prostate cancer in older male dogs. This is because testosterone, made by the testicles, is not involved with prostate cancer, although the exact cause of canine prostate cancer is unknown. Fortunately, prostate cancer is one of the rarest types of cancers a dog can get, according to "Dog Owner's Home Veterinary Handbook."