What does it mean to spay or neuter (sterilize) an animal?

To sterilize an animal means toremove its reproductive organs and permanently stop its ability to reproduce.The term “spay” refers to the surgical procedure used on female animals; “neuter” is commonly used to refer to the surgery performed on males.

There are 3 possible ways to spay a female cat. Our vets choose one of the first two, depending on the cat’s condition and circumstances: 

Ovariohysterectomy: the ovaries, fallopian tubes and uterus are removed from a female dog or cat. This makes her unable to reproduce and eliminates her heat cycle and breeding instinct-related behavior. For decades this was the typical “spay.”

Ovariectomy: the ovaries are removed from a female dog or cat, but the uterus remains. Similar to ovariohysterectomy, this makes her unable to reproduce and eliminates her heat cycle and breedinginstinct-related behavior. This has become the standard procedure in the EU, and is now being used more in the US as well.

Hysterectomy: the uterus and part of the fallopian tubes are removed from a female dog or cat. This makes her unable to reproduce, but her ovaries remain and will produce hormones. This may not eliminate the dog or cat’s behaviors associated with the breeding instinct.

There are 2 common ways to sterilize a male cat:

Orchiectomy, or the typical “neuter”: the testes are removed from a male dog or cat. This makes him unable to reproduce and reduces or eliminates male breeding behaviors. 

Vasectomy: only the vas deferens, which conducts sperm from the testes, are removed. This procedure makes the dog or cat unable to reproduce, but his testes remain and will produce hormones. This may not eliminate the dog or cat’s behaviors associated with the breeding instinct. 

Source: American Veterinary Medicine Association.