In the book "More Joy With Icelandics", in an interview with Rikke Schultz, DVM, Sweden, it states:
"Studies have shown that the forepart of the digestive tract, stomach and
small intestine, or an Icelandic is considerably smaller than in other light
horse breeds and the rear part is considerably larger. The volume of the
stomach is only 2% of the total digestive tract in Icelandics. In other
breeds it is 9%. Foreign data also shows that the large intestine makes up
61% of the total volume of the digestive tract in other horses. In
Icelandics this proportion is 71.8%. An American study showed that in other
breeds the length of the digestive tract measures 21.78 meters and in the
Icelandics the large intestine was 1.23 meters longer."
We have done some searching to determine if this is fact or fiction.
First, we asked other pony owners if they knew of any differences in the intestines and stomach of ponies versus that of horses.
Here are some of the answers that we received:
From a Vet:
As far as I know the ponies and horses are relatively the same. I have not
heard nor have I seen any differences, I've done colic surgeries on both and
can't say there was and difference. All equids have small stomachs and no gall
bladder because their evolution is as a grazing animal. Therefore they are
programed to eat many small meals and have no need for a large stomach. Their
ceacum and colon on the other hand is very large to accommodate the break down of
Hope this is clear and helps.
No difference according to my husband (a horse vet), who has done
colic surgery on everything from minis on up to big old draft
horses. Ed says "We used ponies in vet school to learn how to do
colic surgery, etc., since they were proportionately smaller overall
but their intestines were otherwise perfect replicas of those of
Anatomically speaking there is no significant difference between a pony and
a horse of similar size. Obviously large horses have larger intestines and
small one have smaller ones.
But there is no difference in proportion between a pony and a horse, other
than those associated with the size differences.
Some ponies can have different metabolisms from highly bred horses such as
He said he's never done colic surgery on an Icelandic. . . but there
should be no reason they are different. . . If you come across a
reference that says otherwise I'd love to see it!! It could be another
one of those "myths" about horse breeds that is handed down as gospel,
even though it has never actually been proven scientifically! Even
though Icelandics are considered an old purebred, they originally came
from a combination of Scandinavian stock plus stock from British Isles.
There are some traits Icelandics have that are common with Fells.
While the overall anatomy of the gut may be the same, it does not mean
that this or that breed is not better adapted for different forages.
Eg., with different enzymes in gut to digest certain sugars/proteins,
You can also see the same kind of thing in humans as far as enzymes -
eg., certain ethnic groups have poor ability to digest certain things
(eg., Asians/Africans tend to have lactase deficiency - something like
more than 90%).
Or different jaw/tooth structure - with some breeds being built to be
more efficient at grinding course roughage. A pony with a deep, curved
mandible, with long, deep crowns, and incisors angled to "cut" rather
than tear, are very efficient in grinding their food. Those with flat
mandibles with short crowns are less so.
Dr. Deb Bennet and also Eyjólfur (Jolle) Isólfsson (Head riding teacher at Holar College) were asked. Dr. Deb indicated that there are no differences between pony and horse intestines and stomachs. Jolle was less definite in his answer, but didn't think there would be a difference.
Rikke indicated that the source of her information was one of her late professors from vet school, who was very
interested in this, and that she would try to find out more.