There are multiple types of uroliths. They arise for different reasons. Yes, there are also ones caused by too much vegetable matter and also affect the urine pH differently. In fact, those struvite stones have been the more common form of stones in ferrets. Here's are some articles on them: http://www.vin.com/VINDBPub/SearchPB/Proceedings/PR05000/PR00299.htm http://www.ncbi.nlm.nih.gov/entrez/query.fcgi? cmd=Retrieve&db=PubMed&list_uids=3451569&dopt=Abstract Now, cystine stones are increasing found in testing labs. The rate change is intriguing and while the postulation seems quite clear it always pays to do the actual research to get a handle on a problem. When that can be done for an emerging problem before it has a chance to become common so much the better because that is the best way to help. That help explain it? I didn't realize there was more than one type of urolith in ferrets, either, till we wound up with two having them. What a way to learn! It's late again so rather than read or even skim some resources for you I'm going to pull up some by a recognized expert even if the animal type is wrong because the general info will be there. Here's something on Cystine stones: http://w3.vet.upenn.edu/research/centers/penngen/research/ cystinuria_update.html and here are struvite stones and on calcium stones for you: http://www.vin.com/VINDBPub/SearchPB/Proceedings/PR05000/PR00125.htm Here are photos of a range of kidney stone types including a struvite one from a ferret (Notice the large range of types and each is going to have it's one way of forming in whatever gets it.): http://www.herringlab.com/photos/ Anyway, you can see why it is so essential that the stones themselves be analyzed. Different approaches are needed to prevent a repetition of each type. What works for one stone type is not going to be the right corrective measure for some other types, in fact, when it comes to adjusting urine pH some stone types happen more with alkaline urine and others happen more with acidic urine so if the urine pH is manipulated without knowing what type of stone is present but the guess is wrong... (Moral: also test urine pH when stones occur!) USDA list of renal and urinary pubs on ferrets (including Dr. Dutton's cystine stone article): http://www.nal.usda.gov/awic/pubs/ferrets/renal.htm The new study on cystine stones (cystine uroliths) in ferrets is being coordinated by Dr. Michelle Hawkins VMD DABVP (Avian) who your vets can reached at: 2108 Tupper Hall, University of CA, Davis, CA 95616 1-530-752-1363 (phone) [log in to unmask] Please, let your ferret vets know about this new study and give them that contact information in case they run into a ferret or are treating a ferret or ferrets who have or have had cystine urolith problems. --Sukie, not a vet and learning about all sorts of things as I go along (even Bubba Ho-Tep) http://www.vin.com/VINDBPub/SearchPB/Proceedings/PR05000/PR00298.htm http://www.vetsoftware.com/acvc2002-hess2.htm http://www.bubbahotep.com/ http://www.retrofuture.com/ http://www.eweek.com/article2/0,1759,1749948,00.asp?kc=EWRSS03119TX1K0000594 http://www.apple.com/macmini/design.html and http://www.apple.com/ipodshuffle/ http://www.betterhumans.com/News/news.aspx?articleID=2005-01-11-3 [Posted in FML issue 4756]