by Amanda L. Maus DVM
First, let's start with what a spay or neuter procedure entails. A male cat has his testicles completely removed in a surgical procedure called a neuter, castration, or sterilization . A female cat has her ovaries and uterus removed in a surgical procedure called an ovariohysterectomy, spay, or sterilization. Many animal shelters and rescue groups will perform this procedure as early as 8 weeks of age or when the kitten reaches at least two pounds in body weight. Most veterinarians perform this procedure by 5 - 6 months of age before the sexual hormones become apparent.
If a female cat is not spayed by 5 - 6 months of age, she will go into heat, also called estrus. During her heat cycle, a female cat may try to escape the house or yard in search of a mate. She will be very vocal and extra affectionate. A female cat can come in and out of heat every few weeks, unlike a dog. Each heat a female cat goes through greatly increases her risk of having malignant breast cancer later in life. Unneutered male cats will come around the house or yard due to sensing the pheromones her body is producing. Male cats over 6 months of age become territorial. They will get into fights with other males causing infected bite wounds and contracting diseases like FeLV and FIV. They will also start spraying urine to mark their territory outside as well as inside. A pair of intact cats can produce three litters of 4 - 6 kittens in a year!
Feral or stray cats are at the highest risk for the above consequences since they are not housed away from other cats. There are TNR organizations that can help with trapping, spaying or neutering, and releasing these cats back into the wild.