My wife works for a vet, I had her read this thread. Her thoughts:
Normal incision is about 3/4" for her vet. 2 sutures.
On occasion, a small piece of ovarian tissue may be left within the cat. It is also possible to find 3rd ovaries in cats. When this happens the heat cycle is uninterrupted and further surgery is necessary (we have owned such a cat).
It is also possible for cats to be hermaphrodite. She has seen 2. They usually have a noodle and ovaries, sometimes a testicle. When this happens a simple spay turns into abdominal surgery, necessitating a slightly larger incision.
Sling, male cats can be cryptorchid, where one or both testes have not descended from the abdominal cavity (this is also abdominal surgery, larger incision). Even so, they have never made such a mistake at the clinic.
If the surgery is performed in a surgically sterile enviroment there should be no need to "treat" the incision with anything at home. They swab the incision off with 1% peroxide after surgery just to get the blood off.
5 cats, 4 dogs, birds, rodents, etc etc all in my house. We get a lot of... rescues from the clinic. Last thing she brought home was a Great Dane puppy. Brought home a 4 foot iguana in a cat carrier once. Tried to bring home a pot-bellied pig. The boys and I were in the back yard digging a BBQ pit for it. She took the subtle hint.
General rule is anything over a couple hundred pounds has to live in the barn with the horses...
... it's not so bad, I have had worse room mates.
