Everyone knows they should have their females dogs and cats spayed, but what exactly does that mean? The word "spay" is thought to originate from the Old French espeer meaning to cut with a sword, which then may have been changed to the Middle English spayen. Today the word means to perform a surgery to remove the reproductive tract from the abdomen of a female animal.
A spay is not a simple little surgery. It is not a tubal ligation. A spay surgery is a major abdominal surgery that removes the ovaries and uterus. An incision is made on the mid-line of the abdomen, each ovary is isolated, ligated and removed, then the body of the uterus is ligated and removed.
This surgery is performed in order to prevent pregnancy of course, but there are two other reasons veterinarians recommend the procedure. The two reasons are: to try to prevent breast cancer and to prevent a pyometra. If a dog is spayed before her first estrus (heat cycle), veterinarians just don't see breast tumors. If a dog goes through one heat cycle, she has an 8% chance of developing breast cancer. If a dog has two or more estrus cycles, she has a one-in-four chance of getting breast cancer.
A pyometra is a bad infection of the uterus that requires immediate surgery to remove the swollen uterus along with the ovaries. This is considered an emergency, it is essentially an abscess in the uterus. These dogs are sick and require hospitalization with intravenous antibiotics and fluids until they are feeling better. This is fairly common problem in unspayed female dogs, with the odds increasing with age. It tends to occur a few weeks after an estrus cycle.
When women have a hysterectomy, the ovaries are often left in the abdomen. This is not done in dogs because they would still come in heat and they would still be at a high risk of breast cancer.
The traditional age to perform the spay surgery is six months of age. The first estrus cycle is usually between seven and nine months of age, and we want the surgery to be done before this.
Some rescue groups are doing spay surgeries at younger ages as their motivations are population control. They want to make sure all puppies and kittens that are adopted have no chance of having litters of their own.
In summary, while a spay surgery is a commonly performed procedure, it is not a simple surgery, or one to be taken lightly. Talk to your veterinarian if you have questions about getting your pet spayed.