Okay, well, I got the number wrong from memory: 50% is right. I'll post the correction. Here is a past post of Dr. Bruce Williams, who is at least one of the world's top ferret expert veterinary pathologists (Some other experts refer to him as the best; all are agreed that he is really up there.): http://ferrethealth.org/archive/browse.php?msg=SG3097 >Adopting a female in heat means that you will have vet bills right >away. The first thing to do is have a complete blood count done at >your vet - to ascertain whether she is anemic and how bad the anemia >is. If she is weak, and pale when you get her, the anemia may be >advanced. However, also remember that only 50% of jills suffer from >anemia as a result of persistent estrus. >Regarding treatment - if her blood count is over 25%, don't worry >about the shot - just have her spayed. A shot may be benefitical >for ferrets with a hematocrit less than 25%, to buy some time until >she is a stronger surgical candidate. IF the blood is less than >15%, a transfusion and the shot will be necessary. > >With kindest regards, > >Bruce Williams, DVM BTW, adrenal growths also sometimes cause estrogen toxicosis. In the second edition of _Biology and Diseases of the Ferret_ you will find it on pages 47 and 48. [See correction nect post. BIG] Page 218 in _Biology and Diseases of the Ferret, 2nd edition_ but notice the mention that in Black Footed Ferrets and Siberian Polecats bone marrow depression had not been documented. Pages 137-139 in _Essentials of Ferrets, a Guide for Practioners_ (the second edition, by Dr. Purcell) Anyway, those are some places to begin looking. The second ferret we ever had (a breeder retired after a male bit through one of her eyes while mounting) had to have an emergency spay before coming home with us due to the onset of marrow suppression. That was a long time ago now -- maybe 24 or 25 years ago. -- Sukie (not a vet, and not speaking for any of the below in my private posts) Recommended health resources to help ferrets and the people who love them: Ferret Health List http://www.smartgroups.com/groups/ferrethealth FHL Archives http://ferrethealth.org/archive/ AFIP Ferret Pathology http://www.afip.org/ferrets/index.html Miamiferrets http://www.miamiferret.org/fhc/ International Ferret Congress Critical References http://www.ferretcongress.org [Posted in FML issue 5196]