I doubt if the FML was out more than an hour before I started getting lots
of emails concerning body size and skeletal growth. Here are a few answers
to many similar questions.....
Osteoporosis simply means the bone is getting more porous; the amount of
bone mineral declines and bone spaces become larger. In animals with large
body weights, such as people, the risk of fracture and deformity becomes a
problem. In lighter animals, such as ferrets, osteoporosis is not nearly
as much of a problem, especially in terms of fracture. I called a few
vets and the vet hospital and was told the risk of bone fracture due to
ostoporosis in ferrets is limited to those with extremely advanced cases,
which is uncommon except in conjunction with other diseases (usually kidney
and related diseases).
Osteoporosis can be caused by many factors--some of which are species
unique--and beyond the scope of an FML post. But there are two factors
that ferrets owners should be aware; neutering and exercise. Exercise is
one of the best ways to increase the thickness and decrease the porosity
of bone because as the muscles increase in size and strength, they cause
biomechanical forces to stress the bone, which increases the deposition of
bone minerals. In short, the more you exercise, the thicker and healthier
your bones become. Neutering in females has the same type of effect as
menopause; the loss of hormones inpairs the bone's ability to maintain
itself, and the bone thins and becomes more porous. In males, neutering
has two effects; first, it decreases the skeletal growth rate making the
ferret smaller. Second, it also results in thinning and porous bone, but
probably not to the same degree as in females.
What does the ferret skeleton look like in neutered ferrets? I will
describe a single bone, the femur (the other bones react similarly). In
both male and female whole ferrets, the femur is a robust bone, and fairly
thick compared to most other animals of the same weight and size, such as
squirrels. Male ferret femurs are 15-30% larger than those from females.
Femurs from early-neutered ferrets are substantially lighter, and somewhat
shorter. Sexual dimorphism (females being smaller than males) still
exists, but the males are only 5-17% larger, a significant decrease in
dimorphism. Exams that test the density of the bone show a 10-25% loss of
density, which means the bone is lighter and more porous.
The differences are so significant to the trained eye that if you placed
neutered and whole male skeltons on the table, I could easily separate them
at a 95% or better rate. The same is true for females. In tests of mixed
skeletons, I am just as good *IF* the skeletons are complete enough to
allow sexing, but from individual bones, my success rate is about 85%
because the whole females tend to overlap the neutered males in size.
Most diets are fine for healthy adult animals. But sick animals have long
been recognized as needing additional nutritional suppliments to "put the
weight back on." The need for additional nutrients in growing animals has
also been long recognized. Building bone is not much different from
constructing a building; you need X amount of rebar (bone matrix) and Y
amount of concrete (bone mineral). Limit any part of either, and you
simply don't have enough materials to build the structure as high as you
want it to go (skeletal growth). Only by providing the raw materials IN
EXCESS of needs can you ever be sure of building the structure as high as
possible by the contract deadline (growth period).
In ferrets, this simply means the diet must contain slightly more protein,
fat and bone minerals than the ferret can use; the rest just passes through
in healthy animals. Notice I *DIDN'T* say carbohydrates? Kibbles are 60%
or more carbohydrates, which means growing ferrets have to suck down a
tremendous amount of food to equal the same intake of proteins, fats and
bone minerals of animals eating a "natural" diet. That results in an
increase in food costs, production of poopie, AND fatter ferrets. A person
wrote to brag THEIR ferrets were 5 lbs, and attached a picture to prove it.
The photo showed an obese ferret; my 5 pounders are quite lean. In fact,
because muscle is heavier than fat, mine *look* 3-4 lbs, but are much
heavier. Before Carbone went into rut, he topped 6 lbs.
One of the ways I've found to make sure the ferrets maximize their skeletal
growth is to feed them lots of chicken and turkey, including the skin, fat
and bones. If you are afraid of bone splinters (I have *NEVER* had a
problem in literally thousands of bone feedings), then instead of feeding
them limb bones, feed them the neck and back bones WHICH DO NOT SPLINTER
BUT CRUSH! My ferrets gnaw on these bones much like a dog, all my ferrets
have strong, dense skeletons, and none of my carpet monkeys chew cloth,
rubber, electrical cord or toys. BTW, chicken necks are the best! My
ferrets LOVE them!
Finally, once the skeleton has reached its adult size, the growth centers
fuse and the bone can no longer grow. But it does continue to create new
bone to replace older and dead bone, and ultimately the entire skeleton
will be replaced, one osteon at a time. So adult skeletons are continually
replacing themselves, but they don't grow. Placing a ferret older than a
year on a "growth diet" will fail to make thier skeletons grow larger.
One final myth to debunk. Eating bone is not the same as eating the "ash"
found in most foods. Ash is the minerals left over when a carcass has been
tested for composition and calorie value. True, it is mostly bone
minerals, but bone can be a vastly different substance. With "ash," you
have no idea of the chemical composition of the minerals, nor of their
proportions. With fresh bone, you know the protein/fat/mineral content is
perfectly balanced, as is the proportions of calcium to phosphate. Eating
too much calcium OR phosphate can cause formation of stones, arthritic
process and thinning of bones. But those problems do not exist when
healthy ferrets eat bone where the minerals are proportional.
Bob C and 20 Mo' Belching Bone Munchers
[Posted in FML issue 2526]
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