Spayed but still exhibiting sexual behavior

Question
Hello Norman,
We adopted two semi feral female cats and had them both spayed at around six months old when both were showing definite signs of being in season. After the operation the vet explained that this was indeed the case but hormone levels were higher in one of the kittens and she was still calling to male cats ,rolling around, and disappeared for a couple of days, When she returned she had settled down and stayed around the house for around a month. However,yesterday she disappeared again, returning this afternoon again showing distinct signs of being in season. Fed her then let her out whereupon she chased after a local tom who then proceeded to mount her. Does this behaviour indicate that her spaying was unsuccessful, will this behavior subside in time, and would it still be possible for her to breed?  

Answer
Jackie,

Cats are not very big and vets who are used to working on larger animals may, occasionally, miss part of the uterus.  The fact that she has hormone levels too high for a spayed female would prompt a discussion with the vet.  It is highly unlikely that she could carry anything to term, but she thinks she can. The fact that it has been over a month, leads me to believe the spaying was not as successful as it could have been, but I am not a vet.

If the hormone levels begin to subside, it may just be a freak of nature, if, on the other hand, the hormone levels are no different now than they were the last time you had her tested, would make me wonder about the initial spay job.

Most vets, if they think they might have made an error, should be quite reasonable in dealing with the situation.  If you are calm and measured and the vet becomes very defensive, it may be time to look to another vet for a second opinion.

Best regards... Norm.