Message Number: YG1867 | New FHL Archives Search
From: Bruce Williams, DVM
Date: 2001-03-29 23:01:00 UTC
Subject: Re: Dr. Williams - Experience begets Understanding?

--- In Ferret-Health-list@y..., Edward Lipinski <elipinski@j...>

Dear Edward:

I apologize for the brevity of these answers, but the scope of this
post could certainly fill a book chapter (very similar to the one I
am currently writing.) Rather than give the appearance of ignoring a
post - I'll take the easy way out and be brief (realize that under
more normal cirucmstances, my answers probably would be considerably
more verbose.)
> 1.) Do you have now opinion on the long term health status of
> that have been fixed and descented within the second month of life?

I have seen no concrete proof that early neutering increases the
development of neoplasms, especially adrenal. In American lines of
ferrets, intact animals, although extremely uncommon, appear to
develop adrenal lesions at a pace consistent with their more numerous
neutered colleagues.

> 2.) Out of a group of 100 ferrets, the early fixed & descented,
will 70
> of them develop cancer after the 3rd year, the 4th year, the 5th
> Some small percentage, say 30, will never be so afflicted?

These are numbers that I cannot give. My personal practice is not a
random sampling - you would have to follow a closed colony through a
lifespan to generate valid numbers such as you seek.
> 3.) Any way you know of comparing the incidence of 'cancer' in such
> ferrets as defined above to those ferrets that are fixed &
descented just
> prior to puberty - say 5 months of age or older? Or never fixed nor
> descented?

None. Very few ferrets have histories as to when they are
descented. Once again, this type of study would have to be designed
and executed very carefully, and in the current economic climate, it
is highly doubtful that such a study, with no marketable endproduct,
would be conducted.
> 4.) Can you say that inbreeding of ferrets has no known
consequence in
> terms of the apparent high incidence of 'cancer' in ferrets that we
> today in the overall ferret population? I am assuming that the
> ferret population is roughly known and that the percentage of pet
> ferrets within this population is also known. What? Something on
> order of 98 percent of the latter.

I am not sure of the veracity of these numbers, but I am fairly
certain that "inbreeding" would lead to the same genetic flaws in
ferrets as we have seen in numerous other species.
> 5.) As an experienced vet, how would you compare the incidence of
> 'cancer' in family pets other than ferrets? With the pet dog,
> some are fixed at young ages, hardly any are descented, or so it

I don't think that descenting would have any effect on the
development of neoplasms in any species. I am not familiar with
other species with such a high incidence of endocrine neoplasms as
ferrets, but ferrets on the other hand, have far fewer testicular
tumors than the dog, for example. Each species has its own peculiar
incidence of various diseases and neoplasms, and ferrets are no
exception. The interesting part about ferrets, however, is th
increased incidence of neoplasia in American bloodlines, which to me
suggests a certain genetic predisposition.
> 6.) Do you think it would be pointedly significant if those ferret
> patients who were asked and wished to do so would please give the
> of their ferret(s); i.e. pet store or a private ferret breeder, so
> slowly over time, the answers to such questions as above could be
> answered one way or another as to the long term health effects of
> fixing of ferrets?

Significant perhaps, pointedly no. There have been numerous attempts
to generate such information by surveys within the ferret community,
and none have been successful. The only way to generate valid data
of this type would be to split a colony of ferrets in half - neuter
50% early, 50% late, and see what happens over a lifetime. Once
again, not economically feasible.

> 7.) As is readily seen sexual dimorphisim is quite marked in non-
> ferrets (male to female relative size) so that an illuminating
> can be seen in the degree of sexual dimorphisim between fixed and
> ferrets. Since this outward quite visible difference is seen,
there must
> be also significant differences in the body intertior too. We can
> to fixed ferrets as truly 'stunted' by comparison, surely both
> as well as exteriorly. And that leads to this question, to wit:
What is
> the function of the immature gonads, particularly in the prepubertic
> development of the ferret's immune system?

I cannot agree with your assumption that sexual dimoprhism is any
greater in fixed vs. neutered ferrets. Intact animals generally have
more significant weight fluctuations during the seasonal cycle, but I
would have to see data showing this. I am not familiar with any
significant impact on the ferret's immune system by the gonads,
although I am sure there is some type of interrelation.
> 8.) Probably no answer to this question but what is the incidence
> 'cancer' in the native American Black-footed ferret? Do they live
> enough in the 'wild' to be comparable to in-home, pet ferrets?

The lifespan of the BFF in the wild in unknown, as there are so few
overall, and we do not allow wild BFF's to remain wild. They are all
used in captive breeding programs, and those that are released
following (generally older ones that are beyond their quality
reproductive years), live significantly les than a nomral lifespan.
My experience with BFF's show a lesser incidence of neoplasia, and
the types of neoplasi are far different. I have yet to see a case of
adrenaldisese in a BFF, for example.
> 9.) Why is the incidence of 'cancer' so very much higher in USA pet
> ferrets than in other countries where ferrets are kept?

That is a wide open question, and there are many possible answers. My
personal belief is that it is genetically bred into the American
ferrets, which started with a relatively small gene pool producing
the vast majority of animals for the pet trade. We also have a very
high incidence of other diseases, such as cardiomyopathy in American

Other people may point to dietary influences, the influence of
photoperiod, etc., but a genetic background appears to be the most
able to explain the tremendous differences in ferquency between
American and non-American bloodlines.

With kindest regards,

Bruce H. Williams, DVM, DACVP
Join the Ferret Health List at