Spay and neuter are the common terms for permanent surgical removal of the animal’s reproductive organs. Spay refers to removing the uterus and ovaries in females, and neuter refers to the removal of the male’s testicles.
Beside the obvious advantage of preventing unwanted puppies and kittens and avoiding the whole discomfort that owners experience with the female heat and the males response to it, there are few important medical advantages of performing spays and neuters.
Medical advantages in females:
Prevention of mammary tumors (breast cancer): mammary tumors in animals are usually hormone dependent, if the queen (female cat) or bitch are getting spayed before their first heat cycle their chances of developing mammary tumors are 99.5% less than that of an unspayed female.
If the female is spayed after she had one cycle, her chances of developing mammary cancer are 92% lower than that of an unspayed female.
After the female had two heat cycles, spay will not prevent mammary tumor. Hence the best timing for female spay is before her first cycle, which is generally around 6 months of age.
Uterine cancer and ovarian cancer are prevented due to the removal of the susceptible organs.
Prevention of uterine infection (pyometra). Pyometra is a condition in which the uterus get infected and get filled by pus. The condition has two forms, open pyometra occurs when the uterine cervix is open and pus discharges. This form is less dangerous because it is easier to diagnose. Closed pyometra occurs when the cervix is closed and pus accumulates in the uterus which potentially causes uterine rapture. Pyometra is an important disease to be aware of for any dog owner because of the sudden nature of the disease and the deadly consequences if left untreated. Pyometra is a result of hormonal changes, hence spaying the animal will prevent it by eliminating the susceptible organ and the causative hormones.
Medical advantages in Males:
Neutering males in early age helps preventing aggression towards other males.
Intact males tend to suffer from benign (non cancerous) enlargement of the prostate gland which due to its anatomical location may interfere with urination and defecation.
Male cats tend to spray their urine around the house as a sign of territorial marking. Neutering the tom cat around the age 6 months usually prevent this disturbing habit.
Despite the many advantages the procedures have, it should be noticed that spaying and neuters are done surgically under full anesthesia. The procedure bears some risks as with any surgical procedure. Immediate complications of neutering include anesthesia related death, bleeding and infection. These risks are relatively low in routine spaying and neutering; however, they may be increased for some animals due to other pre-existing health problems.
Other main disadvantages of altering pets include: Neutered male cats have greater chances of developing lower urinary tract infection including presence of urinary crystals or stones. Spayed females can develop urinary incontinence due to the lack of estrogen. Both of those conditions are medically manageable.
Despite the possible complications of the procedures, spay and neuter are still recommended by veterinarians.
I hope this brief article shed some light on the reasons for this collective recommendation.