I have a bit of bladder stone info for you, and will be doing some
near-future posts.
 
Dr. Carl Osborne says in part that he does not consider uroliths to be
unusual in ferrets and
>The Minnesota Urolith Center has received in excess of 100 urinary
>stones from ferrets.  The most common type is sterile struvite (75%).
>Other types include calcium oxalate (12%), and cystine (4%).
 
and Doctor Michelle Hawkins of UC Davis reports that in the last year the
numbers of cystine stones and cystine crystals which they have seen have
suddenly greatly increased in their lab.  (I just got permission to share
this with you; it's brand new info.)
 
Cystine stones in many mammals are inclined to involve a genetic kidney
factor and to also involve input from diet, esp. ones high in the COLA
grouping of amino acids (protein building blocks).  As one of our FHL
members mentioned in the past, some write-ups also talk about some
possible drug causes known in humans.  So, the question becomes why
there is an increase seen now.  Better medical care?  More breeding of
some lines that have a vulnerability?  Higher protein diets showing
a vulnerability in some ferrets which doesn't show up with the older
foods?  Etc.  Exactly what is happening with ferrets is still unknown
so right now it's a matter of best-guess scenarios.
 
There is a treatment protocol for these in the post of a member who had
a past ferret with successful management after past repeated cystine
stones.
 
(We had our first ferrets -- 2 of them -- with uroltihs this year after
having never encountered them in 23 years with ferrets and had to
suddenly begin to learn about this topic.)
 
Uroliths vary with which urinary pH is best and in cause.  For more on
the topic, see past posts in
http://fhl.sonic-weasel.org
 
Our current mode here -- since the stones were removed -- is that the
ferrets are back on the standard lower-than-the-latest protein foods
(like MF, Ferret Store Supreme, Totally Ferret, 8 in 1 Ultimate, PV,
etc.) and they are having regular urine pH checks here and regular exams
and testing/imaging.  We may in the future have to try to shift to an
even lower protein diet or try to meds, or both.  The meds involved can
sometimes involve some very serious side effects so the general wisdom
has so far been to see if the problem recurs before jumping to that.
[Posted in FML issue 4624]