cockerduchess,
The presence of that Male could very likely be it, I say that because there are SO many variables. We forget that the surgery (Spaying) was not done on their Noses, Eyes or Ears, and all those continue to work real good.
The fact remains, that He may not be attracted to Her, considering Alterations, but, that doesn't mean that She isn't still attracted to Him (being in tact). IMHO, their desire for Social and possibly Sexual Contact remains to some/large degree, no different than those feelings in Humans.