Dear X - There may be a common thread here between the hair loss and straining to urinate. Ferrets with adrenal disease may show hair loss (although tail hair loss is not specific) and prostatic disease (which compromises the ability to urinate) due to the production of excessive levels of estrogen. Adrenal disease should definitely be discussed at your Monday visit. However, you should also realize that the two conditions may be totally separate events. Crystalluria is occasionall seen in ferrets, but today is seen much less frequently than the dysuria of prostate disease. Neoplasia of the lower urinary tract, to include the prepuce may also compromise urination, but these tumors are quite rare. Cystocentesis (removing urine from the bladder via a needle inserted through the body wall, is a useful test which is less traumatic then it sounds. However, to be performed successfully, the ferret must be calm (sometimes lightly anesthetized, and have a full bladder. This test is excellent for identifying bladder infections and may even be useful in the diagnosis of some neoplasms. Any blood, inflammation, or bacteria seen in a cysto sample, by definition, MUST have arisen in the kidney, ureter or bladder. Good luck on Monday bruce williams,d VM [Posted in FML issue 3459]