One note may also be helpful for any who do not know the structures involved, a second note for any who have a ferret with sludge in the urethra and their vets, and third a link to a useful article if I can find it and other ref(s): 1. The kidneys (sometime one horseshoe shaped kidney in humans but I do not know how common that anatomical variation is in ferrets) have a tube on each side, the ureters, which lead down to the bladder. Ureters can have problems of their own, problems which was come down into them from the kidneys, or problems that can be pushed up from a bladder. Then there is the urinary bladder, and then the tube out is the urethra. 2. We had two ferrets with cystine uroliths in our decades with ferrets and the female was easily treated but the male got slush in his urethra which then blocked. There IS a surgery that is similar to the one done for male cats in this situation where a new urinary outlet is created, but our vet first tried repeatedly removing urine from the bladder with a needle, which our ferret seemed to mind less than the overly full bladder. It possibly created backwash because the sludge wound up dislodging and he regained the ability to urinate again after a few days. Of course, the problem is that for most ferrets acquired it is not possible to know if they have the genetic cystine urolith vulnerability which makes high protein diets and possibly things like peas a risk factor. An increase in the rate of cystine stones from ferrets began to be reported as soon as high protein diets appeared. Such a sudden change in rate is not going to be because the vulnerability increased. It will instead be because the previous ferrets were on what for decades was typical: a 35% protein diet, and that level is low enough that most ferrets with the vulnerability do not develop stones on it. Our two lived nicely into senior years with a diet of no more than 35% protein after their problems in their first years from the COMBINATION of them being among the ones with the genetic vulnerability and the high protein diets they were on. I do NOT know how much cystine (or COLA Group of amino acids which are building blocks for proteins) might be too much for a ferret without that genetic vulnerability or if that is even possible, though everything has an upper limit, sooooooo... 3. <http://www.smallanimalchannel.com/ferrets/ferret-health/bladder-stones.aspx> The above is a fun and useful read for anyone. Dr. Osbourne is one of the urolith experts who helped us with our two ferrets: QUOTE J Am Vet Med Assoc. 2013 Apr 15;242(8):1099-103. doi: 10.2460/javma.242.8.1099. Epidemiological evaluation of cystine urolithiasis in domestic ferrets (Mustela putorius furo): 70 cases (1992-2009). Nwaokorie EE, Osborne CA, Lulich JP, Albasan H. Source Minnesota Urolith Center, Veterinary Clinical Sciences Department, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55108, USA. Abstract OBJECTIVE: To determine the prevalence of cystine uroliths in domestic ferrets with urolithiasis and determine whether age, breed, sex, reproductive status, anatomic location, and season are risk factors associated with cystine urolith formation. DESIGN: Retrospective cross-sectional case-control study. SAMPLE: Records of 435 ferrets (Mustela putorius furo) with uroliths submitted for analyses between 1992 and 2009, of which 70 were cystine uroliths. PROCEDURES: Specific descriptive information was obtained about each ferret to determine whether specific risk factors were associated with the development of cystine uroliths. RESULTS: Cystine uroliths comprised 70 of the 435 (16%) uroliths. Cystine uroliths were more common in male (n = 54) than in female (16) ferrets. All cystine uroliths were retrieved from the lower portion of the urinary tract (bladder and urethra [n = 67]) or were voided (3); none of the uroliths were retrieved from the upper portion of the urinary tract (kidney and ureters). CONCLUSIONS AND CLINICAL RELEVANCE: Awareness of the prevalence of cystine uroliths along with knowledge of etiologic, demographic, and environmental risk and protective factors for urolithiasis may facilitate development of surveillance strategies that result in earlier detection of cystinuria. Genetic factors associated with this disease have not yet been reported in ferrets, but a familial pattern of inheritance determined to be a major underlying factor in cystine urolithiasis in dogs and humans suggests that this may be a factor in ferrets and that the parent stock of ferrets in the present study may have been inbred. PMID: 23547673 [PubMed - indexed for MEDLINE] END QUOTE Also look up Cystinuria Also, my notes show a paper came out indicating the tetracycline in some species can cause cystine to precipitate out. In ferrets? Unknown. Okay, it took a while with many search terms, but after recalling who posted it here is this for those who need meds for cystine uroliths specifically: http://ferrethealth.org/archive/YG13030 Amy and Dave talk about using a med combo successfully for one who could not be maintained by diet, including: >She was put on 1.0 ml of Tiopronin 2x/day and 0.5 ml of >Policitra-K once a day. She had one more surgery several >months after that to remove a number of stones, and then never >had another problem with them her whole life. She had periodic >bloodwork run to make sure the medications did not harm her, >and she lived to be almost 8. (She ended up with a whole host >of other things -- cardio, adrenal, abscessed tooth -- at one >point she was on 5 or 6 meds a day.) REMEMBER: Any ferret who gets cystine uroliths is going to be vulnerable to getting them again because of the genetic vulnerability which is why their diets always afterward need to be no more than 35% protein, they need to have their urine pH watched so it does not drop too low, some need medications, and it is certainly possible that peas -- and some OTHER foods or food combinations -- might cause similar problems for this subset of ferrets according to the mechanism in which sulphur aids the body in changing methionine (another amino acid) into cystine which is in my last post which was sent to me by a British biochemist. Sukie (not a vet) Ferrets make the world a game. Recommended ferret health links: http://pets.groups.yahoo.com/group/ferrethealth/ http://ferrethealth.org/archive/ http://www.miamiferret.org/ http://www.ferrethealth.msu.edu/ all ferret topics: http://listserv.ferretmailinglist.org/archives/ferret-search.html "All hail the procrastinators for they shall rule the world tomorrow." (2010, Steve Crandall) A nation is as free as the least within it. [Posted in FML 7971]