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Door ~Joke~
Hi group!

Following "The Raw Truth" article in Dogs in Canada magazine, Dr. Ian
Billinghurst wrote an excellent response and submitted it to them. I
would like to share it with you, and also encourage you to share with
other feeding, breed or show lists --- for instance those that may
receive DIC as members of the CKC. Unfortunately, its possible, but
unlikely DIC will change the schedule of upcoming articles to include
this important piece of factual and educational information so Dr. B has
decided to let it go public now.

My sincere thanks to Dr. B for this wonderful article. I hope you enjoy
it as much as I am. Crossposts - please ensure the article is posted in
its entirety.

Brenda Hagel

Laatst gewijzigd door ~Joke~ op wo 14 sep 2005, 21:16, 1 keer totaal gewijzigd.
Door ~Joke~
The Raw Truth - Separating Fact from Fiction

A comment by Ian Billinghurst

Veterinary Surgeon - Australia

To the Editor(s) of Dogs in Canada,

Dear Madam/Sir,

I read with interest an article by Hilary Watson (HW), which appeared
in a recent edition of "Dogs in Canada".

In this article, HW discusses three rationales she sees as inappropriate
reasons to validate the decision to feed companion animals a raw food
diet. The first rationale is the premise that dogs are wolves. The
second rationale is based on the presence of enzymes in meat. The
third rationale is the contention that raw foods contain nutrients more
bioavailable compared to commercial pet foods. I entirely agree that
choosing to feed raw on the basis of those propositions is highly
unlikely. HW concluded the article with the observation that there are
many sound reasons for choosing to feed a raw food diet, but failed to
mention them. The body of the article presented some 'factual'
material, which did not appear to support her argument. If you will
permit, I would like to share with your readers my further thoughts on
this topic from the perspective of an Australian companion animal

I would first like to mention what I believe would be the only sound
reason one could possibly have to make the decision to follow a
particular feeding paradigm. I feel confident HW would agree that such a
decision would have to be based on the improved health of dogs fed that
way. The gold standard basis for such decision making requires the
results of appropriate studies. This would be the only way to truly
separate fact from fiction. Unfortunately there have been no scientific
studies comparing the lifetime health of raw fed dogs Vs dogs fed
processed pet food.

Because no such studies exist, potential raw feeders need some other
basis on which to make an informed decision. Which brings me to my
next point and it is this. There have been very few people who make
the choice to feed their dogs a raw diet on the basis of the three
rationales discussed in the article. I find that most people base
their feeding choices on the words and experience of a trusted
counselor, usually following a health crisis with their dog(s). This
counselor could be a veterinarian, the breeder of their dog, a dog
trainer, the local pet-store owner or maybe even their neighbour who has
long practical experience of feeding a raw diet

When people make the decision to feed raw, the next question then
becomes, "what exactly is the evolutionary diet of the dog?" And of
course the evolutionary diet of the dog is not the wolf diet, as dogs
have evolved beyond such a diet. For example, where the wolf was and is
predominantly a hunter and very much less of a scavenger, the modern
dog, evolving on the 'rubbish heaps of human habitation for the last
fifteen thousand years, has become predominantly a scavenger and very
much less a hunter. Without going into details (that requires a book!),
the only point I will make at this juncture is that such a diet is still
predominantly raw!

Having made the decision to feed raw, pet owners will only continue to
feed this way if the diet fulfills its promise. I am pleased to
report that most people so persuaded rarely return to kibble feeding.
Additionally, most happily accept the evidence before their eyes, that
raw diets work in producing superior health, without having to
understand why! And this is good news, because the answers to that
question can be difficult to pin down.
Door ~Joke~
However, there are some people who need to understand exactly how and
why raw foods produce their spectacular results. These people belong
to a small and highly exclusive group of dedicated raw feeders who will
use the dog as wolf theory or the enzyme theory or the bioavailability
theory (or some other theory) in their attempt to understand why their
dogs are so healthy. Having found what they believe to be rational
arguments, which they believe explain the obvious improvement in health
seen in their raw fed dogs, these people will often use such hypotheses
in an endeavour to 'spread the word.' They believe such hypotheses
will be highly persuasive to the unconverted.

Which brings us back to those hypotheses.

Can we say that dogs are raw feeders on the basis that they are actually
wolves, do the enzymes in raw foods confer some sort of health advantage
and what exactly is the story of bioavailability in relation to raw
foods? Can we separate fact from fiction in these areas?

1) The claim that dogs are wolves

There is not one reputable scientist alive today, with expertise in the
area of canine evolution, who would dispute that dogs have evolved from
wolves and that is a fact. Most would also agree that the separation
of dog and wolf occurred in the very recent past - probably in the last
15000 years or so. However, having said that, it is equally clear that
dogs are not wolves - that also is a fact. Dogs are dogs and wolves
are wolves and we may add that dingoes are dingoes - somewhere in
between. Yet again, we need to qualify that statement by pointing out
another fact. That is, all three canids will freely interbreed - this
is an undisputable fact. So clearly, all three canids share more than
99% of their DNA - a fact. Equally, it is also a scientific fact, that
this is a much higher percentage of DNA than is shared between humans
and chimps, which is the comparison made by HW.
Door ~Joke~
In relation to that comparison, it is also worthwhile pointing out the
fact that humans and chimps have never been reported as producing viable
offspring, so clearly the chimp/human comparison is not valid in terms
of comparing the genomic or genetic similarity or dissimilarity between
dogs and wolves.
Door ~Joke~
However, when it comes to nutrition, the above discussion is actually
irrelevant. What requires discussion is not the genetic similarity or
otherwise of dogs and wolves. Rather, what we need to discuss is the
question, "do dogs and wolves share similar digestive physiologies?

The factual answer to that question is yes. So no, a Cocker Spaniel is
not a wolf, but they do share a common digestive physiology. And this
is borne out by practical experience (for example, most Australian dogs,
until the mid 1980s were fed a predominantly raw food diet - another
fact). So, from the standpoint of basic physiology, there is no reason
not to feed raw. And we may add or perhaps conclude that the shared
digestive physiology of the dog and wolf, could well be part of the
explanation for the claimed health superiority that raw-feeders make for
their dogs.

In relation to the question of human nutrition vs chimp nutrition, as
cited by the author, I would like to make the point that her conclusion
is not valid. There are many studies, which demonstrate the superior
health of Seventh day Adventists when compared to the rest of western
society - a definite fact. Here we may make the factual observation
that the Adventist diet is more closely aligned to that of our primate
cousins the Chimpanzees. As pointed out by HW, the chimps live
predominantly on food such as vegetation and termites; I would add - in
a similar manner to many primitive human tribes. The fact is that the
Adventist diet is a very healthy diet for humans and is, unfortunately a
long way from the diet 'enjoyed' by the vast majority of unhealthy
humans in Western society. It is also worth noting that both the chimp
diet and the Adventist diet are very closely aligned to diets espoused
by and heavily promoted by health farms (for humans) around the world.
Door ~Joke~
Unfortunately the comparison between cattle and sheep and their copper
requirements, although doubtless factual, bears little relevance to the
question of whether or not we should feed dogs a raw diet. Cattle and
sheep share a similar digestive physiology and they both consume a raw
rather than a cooked diet! On the other hand, the owners of some
Bedlington Terriers may well feel uncomfortable for the safety of their
dog's liver, when feeding their dogs on processed pet foods with their
high copper content!

Finally, in an endeavour to separate fact from fiction, note the
following. Firstly, it is true that for the time our dogs have been
associated with 'mankind who cooks,' some of the food that dogs have
eaten has been cooked. However, it is also true that in that period,
the bulk of the food which dogs have consumed, has continued to be raw -
scraps - mostly derived from mankind's 'rubbish heaps.' Indeed, it
has not been until the middle of the last century that the bulk of our
dogs' diet has consisted of cooked grain. This period of time is an
eye-blink in evolutionary terms, so that clearly, there has been no time
for the dog to adapt its digestive physiology to modern processed
foods. We may therefore conclude that the evolutionary diet of the
modern dog is one that aligns with the extensive practical experience of
Australian dog owners of the very recent past. That is, dogs not only
tolerate raw, but, in accord with the clinical observations of a number
of Australian vets (and many thousands of dog owners), actually require
most if not all of their food to be raw, in order to become and remain
truly healthy.

2) Do the enzymes in meat confer an advantage to raw fed dogs?

Unless one can demonstrate that raw meat contains digestive enzymes,
there is no reason to conclude that their presence may confer a
nutritional advantage. If by the presence of enzymes in raw meat, we
are speaking of the enzymes involved in the general metabolism of the
cell, the answer would have to be that such enzymes can not confer any
particular advantage! These enzymes function at a pH close to neutral
and have no function in digesting proteins, carbohydrates or fats,
rather they are involved in the citric acid cycle, the urea cycle and so
on. What scientists refer to as intermediary metabolism.

However, if we are speaking of the enzymes in lysosomes, then the answer
is, most definitely yes. Lysosomes are organelles found in all cells
and they contain digestive enzymes and that is a fact. Lysosomes have
numerous cleaning up functions within cells (including the removal of
potentially pathogenic bacteria) and they also have the responsibility
of digesting/destroying the cell, which contains them, when that cell is
no longer viable. Clearly, lysosomes are a concentrated source of
digestive enzymes. They function at a pH of 5 - a pH which they also
promote. The enzymes in lysosomes are the enzymes responsible for the
autolysis (self digestion) of dead tissue. We see (and smell) the
results of their activity in corpses left to 'rot' in the sun. That is
a definite and definitely unpleasant, fact.

It is not unreasonable therefore to surmise or hypothesise (and in fact
we know this to be true) that such enzymes are highly active at body
temperature and in an anoxic/acidic environment. This is precisely the
environment we find in a canid's stomach. In other words, yes,
lysosomal enzymes, released by every cell in raw meat, (but destroyed by
cooking) would play a significant role in the digestion of raw meat
within the stomach of a wild carnivore such as a feral dog, a wolf, a
dingo or a wild-cat.

Given that the digestive physiology of the wolf and the domestic dog are
essentially the same, we would have to conclude that lysosomal
digestion would definitely occur in the stomach of domestic dogs (and
cats), if allowed by the carer. Do those lysosomal enzymes confer a
health advantage? The answer to that is - we don't know, but since the
digestive physiology of canids over millions of years has evolved in
concert with the activity of lysosmes, our guess would have to be -
probably yes. I should also add at this point, that dogs, are gulpers
rather than chewers. This means they will send their raw protein into
the stomach in a form where the majority of the meat cells will be
protected from the highly acidic conditions of the stomach. This will
allow the lysosomal enzymes to continue their work at the desired pH -
of 5, for a period of time which would allow autolysis or lysosomal
digestion to play a more than token role in the digestive process of

In relation to the question (raised by HW) of trypsin inhibitors, while
it is true that raw soy beans contain trypsin inhibitors (and cooking
will destroy those inhibitors), no person contemplating a raw diet for
their dog would consider feeding it raw soy beans. On the other hand,
phytate, another antinutrient present in grain, is not significantly
affected by heat and will continue to interfere with the absorption of
certain minerals even after processing.

The thiamine story relates to a solo diet of raw fish flesh. It is the
case that some species (of fish) will contain a thiaminase. As no
competent raw feeder would bother to feed their dogs a solo diet of raw
fish flesh, the facts are, this is not a valid argument against feeding

The invalid raw egg white story has been around a long time. The
scientific fact is that there is sufficient biotin in the egg yolk to
more than compensate for the presence of avidin in the white, so in
practical terms, this is not a problem for the raw fed dog. Practical
experience bears this out. To produce a biotin deficiency, the facts
are, even by feeding pure egg whites and little else, it is almost
impossible to produce a biotin deficiency without also destroying the
gut flora with antibiotics. You see the fact is, healthy gut flora
produce all the biotin a dog requires.

In relation to cooking Vs acid denaturation of proteins, it is not a
fact that such processes are identical in outcome. While it is true
that cooking will denature the protein in a similar fashion to acid in
the stomach, the facts are, cooking will also destroy many other
nutrients which are not destroyed by the acid, including vitamins and
essential amino acids, so once again, this is not a valid argument for
cooking as opposed to feeding raw. Another sad fact about cooking is
that over-cooking (excessive heat applied to food for prolonged
periods), results in indigestible complexes between starches and
proteins - a common feature of cooked and processed pet foods, but
factually (and thankfully) absent in raw foods .

3) The question of maximising bioavailability?

Speaking from the standpoint of evolution, it would seem reasonable to
hypothesise that the bioavailability of nutrients as allowed by the diet
a species has eaten for millions of years, would by definition be
optimal. Such bioavailability will vary enormously from food to food and
from nutrient to nutrient. As this has been well demonstrated by HW, it
requires no further comment. Clearly, using maximal bioavailability as
a rationale for feeding a raw diet would most definitely be invalid and
therefore a poor reason for making the decision to feed a raw diet.

Equally, it is valid to speculate that evolutionary bioavailability may
well explain and confer some of the health advantage that raw-feeders
observe in their dogs.
Door ~Joke~
In relation to bioavailability, it is interesting to note the slogan by
KalKan cat foods as quoted by the author: " a multi-vitamin in every
can." Let us separate fact from fiction by pointing out the following.
The facts are that this is an unfortunate example in that the cat foods
of the time were lacking in sufficient taurine to maintain optimal
health. This lack of taurine not only reflected a failure to use
animal tissue to feed cats (obligate carnivores - fact), but was in many
cases a direct result of the cooking process. This was noted as
particularly so when the cooked food was presented in cans. As a
result, the widely advertised as perfect foods for cats, were
responsible for retinal degeneration, cardiomyopathy and reproductive
failure. Each of these problems is non-existent on a properly
formulated raw-food or evolutionary diet - an easily demonstrable fact.

My experience as a long time raw feeder of my own dogs and as an
advocate of raw feeding in my veterinary practice, validates the view
that a properly formulated or evolutionary raw food diet -fulfills the
promise of improved health. This point of view is also validated by
evolutionary theory.

In conclusion, let me reiteraten that I entirely agree with HW when she
says that the decision to feed raw foods should be based on sound
information, not on emotion or unsubstantiated (or fictional) claims.
To make a decision to feed raw on the basis of the dog being a wolf,
that there are enzymes in raw food or that raw food produces food with
increased bioavailability are very simply invalid reasons for choosing
to feed a raw diet. Attempting to understand why a raw food fulfills its
promises is another issue, with the hypotheses discussed above, having
varying degrees of validity in this respect.

The only valid or rational basis for choosing to feed a raw food diet to
one's dog must be the superior performance of the diet in terms of
reproduction, longevity and freedom from disease processes in the dog(s)
that eat the diet. If this promise is fulfilled, we have separated fact
from fiction.

Ian Billinghurst B.V.Sc.(Hons)(Syd),B.Sc.Agr(Syd).,Dip.Ed.(UNE)

Veterinary Surgeon




Copyright Ian Billinghurst 2005
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