From:
Brett Middleton
Date: 2001-03-29 20:57:00 UTC
Subject: Re: Dr. Williams - Experience begets Understanding?
Sukie took her shot, so I guess this is fair game for any of us. B-)
Edward Lipinski <elipinski@j...> wrote:
> 1.) Do you have now opinion on the long term health status of
> ferrets that have been fixed and descented within the second month of
> life?
What little research has been done on early neutering in other animals
has not found any negative effects on long-term health. I understand
that early neutering (6-16 weeks of age instead of 5-8 months) is
becoming increasingly popular for kittens and puppies because of
benefits such as faster recovery, and because there's less chance of
intact pets getting into the hands of irresponsible owners who just
don't get around to neutering. Remember that pets are most salable
(especially to impulse buyers) when they're very young and cute, so
getting them neutered before they're sold will greatly reduce the
number of unwanted litters to be abused and abandoned.
That said, a study to determine the relationship between neutering age
and health in ferrets would certainly be well worth doing.
> 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 see today in the overall ferret population? I am assuming that
> the overall ferret population is roughly known and that the
> percentage of pet store ferrets within this population is also known.
Oooo, a genetics question! But, one that's very difficult to answer
given our present state of knowledge. Obviously genetics does play a
large role in some diseases, including neoplasms. Inbreeding has been
used to develop strains of laboratory mice and rats that are
particularly susceptible to certain tumors, so clearly this is a
possible consequence when inbreeding ferrets. Of course, inbreeding
has also been used to develop strains of crops, livestock and lab
animals that are *resistant* to certain diseases, so inbreeding can
also be used beneficially. It isn't innately "evil".
However, before we can say whether or not inbreeding has a particular
consequence, first we must establish whether the ferret population *is*
inbred to any significant degree. I have seen no evidence on this one
way or the other. While "pet store" ferrets are popularly *assumed* to
be inbred, our intuition in this matter is notoriously faulty. To give
an example, between 1970 and 1990 there were two enormously popular
Holstein bulls that were widely used by dairy producers in the US. By
1990 these two bulls appeared in the first 6-8 generations of the
pedigree of nearly every existing Holstein cow, and nearly 25% of the
genes in the population could be traced to them. Obviously, the
Holstein breed has a very serious inbreeding problem, right? Nope.
Between 1970 and 1990 the average amount of inbreeding among Holsteins
showed only a very modest rise -- from 4.7% to 5.1%. (Note, these are
not harmful levels of inbreeding in this population.)
But, suppose we knew for certain that "pet store" ferrets were more
inbred than "private sale" ferrets, and that they had significantly
greater incidences of certain tumors. This *still* wouldn't prove that
inbreeding has a causative link to those tumors. We would need
additional data to prove that the tumors aren't related to differences
in how "pet store" ferrets are raised, handled, transported and managed
after sale. For example, it is unlikely that a ferret lover who bought
a kit from a small breeder would feed it low-quality catfood from the
grocery store, while this is an all-too-common fate for a "pet store"
ferret. Perhaps this is the significant factor, and the inbreeding is
just incidental.
In sum, 1) we don't know if US ferrets are unusually inbred, 2) we
don't know if the tumor incidence is unusually high, and 3) we don't
have any data that would allow us to control for other possible
contributory factors even if we did know 1) and 2).
> 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
> source of their ferret(s); i.e. pet store or a private ferret
> breeder, so that 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 early fixing of ferrets?
I'm afraid that this kind of "field data" would have, at best, marginal
utility in answering these questions. We could never be sure that
there aren't hidden biases in the data caused by many other factors
that aren't recorded, including such things as feeding and housing
conditions. To really get to the root of this will require some
carefully designed, controlled experiments.
--
Brett Middleton brettm@a... (706) 542-0986
Asst Rsch Scientist Animal & Dairy Science University of Georgia
*SLMW 1.0* Ferrets: They're not just pets, they're adventures!