I am playing it by ear with my Himalayians. One mama had a litter last July. She did not call again until November. I let her have her litter in January and this time when kits were 10 weeks old, she started calling again. I said "no way" and finally she went out of heat. I can only hope she stays out of heat for a few months. It is a toss up which is worse... to let a cat have two to three litters per year or let them stay in heat much of the time without allowing more than one or two litters per year. Which is harder on them?? I have stud pants for my boy and am comtemplating letting him maul her without actually breeding in hopes that she will go into a flase pregnancy. (My vet said it was ok to do this)This happened when my boy was too young to breed but not too young to try It kept her out of heat for 4 months and gave her a good rest.