[2-part post, combined]
 
Q: "Quick question please.... Many of know that dairy products are not
recommended for ferrets but why not?  The only reason I can I think of
is that it gives them loose bowel movements for a day or two afterward.
Is there a problem with milk solids or some other reason to avoid dairy
products?  Why avoid dairy in ferret diets?"
 
A: Besides, it gives them dairy-rrhea.
 
The problem with feeding ferrets milk is milk sugar (lactose).  Mammals,
as infants, tolerate milk sugar and have the proper enzymes to process
it, so it is no problem.  The problem is, before agriculture and cow
domestication, access to milk was limited more-or-less to the early part
of life.  As a consequence, the ability to produce lactase, the enzyme
that helps digest lactose (milk sugar) is lost sometime after weaning.
 
That is the default pattern in mammals; weaned mammals tend to be lactose
intolerant because the ability to produce lactase is lost as the animal
(person) ages.  When lactose intolerant animals (persons) consume milk
sugar, it is not properly digested because there is no enzyme to break
it apart into glucose and galactose.  The undigested lactose molecules
throw off the osmotic gradient in the bowel, which pulls fluid into the
intestines.  You can do the same thing by drinking Go-Lightly, as anyone
who has had the pleasure of quaffing a gallon of what I lovingly call
"Salted Horse Sweat" can attest.  The resulting stool is runny and
watery -- classic diarrhea.  The undigested sugar in the bowel can
also be utilized by intestinal bacteria for food, resulting in classic
symptoms of gas, bloating, etc., but these problems are limited in
ferrets when compared to humans.  Mostly, they just get a bad case of
the runs.  Other than milk sugar, the rest of the milk is fine and not
a problem.  In fact, it is an excellent food for ferrets, being high
in both fat and protein.  I give my ferrets cottage cheese without bad
effects.  The problem with milk, as I said, is in milk sugar.
 
Milk was part of the not-so-popular "Milk and Bread Diet," from about
the 1830s to the 1930s.  It was during this period of time that milk
production increased, the technology to store and ship milk was invented,
and low milk prices made it affordable to be feed to animals.  The
milk-and-bread diet was stale bread, usually soaked in water and wrung
out, and then covered with cream or whole milk (not separated milk).
This diet was NOT satisfactory, but a ferret could live on it for a year
or two, especially if fed the occasional rat or rabbit so they could
replenish essential nutrients.  It frequently resulted in a disease
called "the scours," which usually ended in the ferret's death, most
likely due to a combination of dehydration and electrolyte imbalance.
There also seemed to be some deaths caused by bacterial infections in
ferrets that had a constantly wet rear end.
 
The diet was mostly popular with city folks who did not know much about
ferrets; I have one book that suggests "scoundrel breeders" suggested
the diet to those put off by animals that ate rats.  It also seems that
it was promoted by some Ohio ferret farms who knew American farmers would
see the diet as economical, being that they had dairy cows, waste milk,
and it was better than throwing away stale bread.
 
One modification of the diet, especially in the USA, used oat or corn
meals instead of bread.  It was never popular with people who knew
ferrets and worked with them.  Ferret people would consistently write
about how bad the diet was, encouraging new or city ferret owners to
abandon it in favor of a meat diet.
 
The main reason I suggest the diet was never as popular as what some
contemporary people think is because of "common knowledge" or "folk
knowledge" bias.  Most ferret owners are painfully aware of what some
people think about ferrets, especially in the area of biting and being
a danger to infants.  Just a few weeks ago, I was talking to the cashier
at Sams, who had asked me why I was buying so many whole chickens.  I
mentioned I would BBQ one, roast one in the oven, and the other dozen
would be fed to my ferrets as chunked raw chicken, Bob's Chicken Gravy,
or Bob's Ferret Chicken Soup.  A lady behind me was eavesdropping, and
exclaimed, "Ferrets!!??  They kill babies and chew off their faces!!"
Once something gets into a culture's folk knowledge, it appears as if it
was far more widespread and accepted than it actually was.  For example,
folk or common knowledge incorporates other myths into the public
perception of ferrets, including that they are rodents (probably because
of association with ratting), that they are horrible biters (probably due
to a combination of ferret legging stories, ferrets never socialized to
people, and ferret abuse resulting in fear biting), that they have no
emotions (probably from lack of proper bonding), that they are
bloodthirsty (probably due to a combination of killing behavior instinct
over-stimulation, caching behaviors, and observations of the killing
bite), they kill babies (I have been unable to document more than a tiny
handful of cases of real injury and fewer deaths THROUGHOUT history), and
they eat a bread-and-milk diet.  Just because something is common or folk
knowledge, it doesn't mean it is correct, that it actually happened, and
that was historically popular.  Folk knowledge bias ALWAYS seems to
suggest something was far more popular than it ever was.
 
There is some evidence that suggests if you feed a ferret milk as a kit
and continue to do so as an adult, the ferret can continue to eat milk
without ill effect.  The idea is the continued diet of milk helps retain
the intestine's ability to make lactase.  This helps to explain why some
groups of people drink milk without problems, while others that are
seemingly in the same gene pool are lactose intolerant.  A lot of
research is being done on this at the moment, and it is likely that
recommendations can shift back and forth before it is finally worked out.
 
Some people recommend just giving cream to ferrets, which doesn't have
as much milk sugar, but the high fat could also cause the runs (for
different reasons).  Some people recommend feeding milk commerically
treated to remove milk sugar, which solves the problem of lactose
intolerance.  Others suggest adding lactase to the milk (tablet or
liquid -- sold under a variety of names), which also seems to help.  I
give natural whole milk (pasteurized, but not homogenized) about once a
week, and I don't worry about the resulting squirts because one runny
stool a week has no health or nutritional consequence.  My ferrets like
milk, I give them a little bit once a week, and then I clean up the poo.
It stinks, but it is not a problem.
 
Bob C
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[Posted in FML issue 5338]