From:
Burgess@swanimalhospital.com
Date: 2001-04-25 07:23:00 UTC
Subject: Re: adrenal shocker
--- In Ferret-Health-list@y..., MC <mustangcharlie@i...> wrote:
> Burgess@s... wrote:
>
> > Lisa,
> >
> > It's not just bad luck. Early neutering increases your chances of
> > tumors, <<< SNIP >>>
> >
> > Best of luck,
> > Mark Burgess DVM
>
> Has there been a study released in the past several months that
confirms that early neutering increases the chances of tumors in
ferrets? I follow the early neutering threads pretty closely and I
don't believe that the information above is clinically correct. Only
opinion.
>
> Would someone care to clarify this?
>
> Thank you
>
> MC
Dear MC,
I discovered adrenal disease (and insulinomas) in the 1980's prior to
any published reports of these diseases and so have been tracking the
incidence of these tumors longer than most people. There is no
question that the incidence of adrenal disease has changed alarmingly
in the decade of the 90's. I used to see 10 to 20 insulinomas for
each adrenal tumor and adrenal disease was an occasional problem of
older ferrets, mostly 5 or older. Now the adrenal tumors are more
frequent than insulinomas, and start at much younger ages. Also I
rarely saw bilateral adrenal lesions in the "old days", and these are
common now. The only thing that has changed significantly in the past
decade is the switch from small local breeding programs (where the
ferrets were neutered at 5 to 6 months old), to huge breeding
facilities where neutering occurs at a few weeks of age. The ferrets
are still fed and housed by owners much as they were in the 80's, so
day cycles, etc, do not account for the change in incidence. I
suppose one could hypothesize heavy inbreeding as a cause, but the
time span is probably too short to change the genetic pool that
severely, and different breeders with different breeding stock all
show the same problem. The only common link is early neutering.
There was a ferret study in Europe in the past 12 to 18 months which
claimed a direct link between age of neutering and adrenal tumors,
although it wasn't a really good study protocol. Also a recent study
in rats (who are not prone to adrenal tumors) produced adrenal lesions
similar to ferrets when the rats were neutered very young. So, you
have to draw your own conclusion, but there is no doubt that something
has radically altered the tumor incidence in the past 12 to 14 years
in American ferrets. It's not just "increased awareness" by
veterinarians. I was very aware of the disease in the 1980's and it
just wasn't that common. To my knowledge no other theory proposed,
really adequately explains my observations over the past 15 years.
Best Wishes,
Mark Burgess DVM