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Introduction
This is not a very technical
description of the ruminate digestive system. This page
is meant to offer a quick study and promote the the
desire to learn more about what should be the reason
ruminates are chosen instead of other livestock.
Check out the
other sources
of information listed below. If you have suggestions or
comments
email them to me. Also
email questions and I will try to help you find the
answers. |
Rumen - The Paunch
The rumen,
often called the cows fermentation vat, is the largest
part of the ruminate stomach. Feed, water and saliva are
enter the rumen through the esophagus and is mixed with
the rumen bacteria that latch on to the surface area and
begin to eat or digest the solid the feed. The solid
feed is swallowed, regurgitated, and swallowed again (Chewing
The Cud). The rumen is made up of several "sacs"
where the contents are moved in and out of.
As the rumen bacteria digest the the
feed they reproduce and are than passed on to other
parts of the digestion system to be used a source of
nutrition. They also synthesize B & K vitamins.
As the feed
is digested by the rumen bacteria some is absorbed in
the rumen and the rest flows into the reticulum.
Once in the rumen the feed is also
sorted with heavy particles (large seeds, grains)
sinking to the reticulum. |
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The reticulum is called the honeycomb
because of the appearance of it's lining. As the smaller
and more dense material is pushed into the reticulum
some of the larger particles are sent back to the rumen.
The small particles and some bypass feedstuff are
ejected along with microbe-laden fluid into the omasum.
The reticulum also the hardware
stomach because it collects trash such as metal, some
gravel ect. |
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Is the combination or the rumen and
the reticulum. While separate sections they function as
one. With feed being moved back and forth between them
until it is ready to move into the omasum. Contractions
originating in the reticulum move around the rumen. This
process involves a wave of contraction followed by a
wave of relaxation, so as parts of the rumen are
contracting, other sacs are dilating. This keeps the
digesta moving aiding in mixing with saliva and microbe
activity. |
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Called the
"manifold" stomach because it has folds similar to pages
of a book where much of the water is absorbed into the
cows system along with some nutrients. |
Abomasum - The true stomach
This the
section of the cows stomach that is most like the
stomach of non-ruminates. Here hydrochloric acid
and enzymes (pepsin which breaks down proteins) are
produced. Other other digestive enzymes from the
pancreas enter the abomasum to aid in breaking down
fats. The acid and enzymes also help prepare microbes in
the fluid to be absorbed and break down by-pass protein
and nutrients in grains to be absorbed in the small
intestine. |
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Suppose a cow
can swallows a two inch cube of food. She eats 8 cubic
inches of food with 24 sq. in. of surface area. Than the
two inch cube is forced back into her mouth and she
breaks this cube into 8, 1inch cubes with a total of 8
cubic inches of food with 48 inches of surface area. The
amount of feed has stayed the same but the surface area
has doubled. The number of rumen bacteria that can
attach to the surface area and eat the food has also
doubled. Every time the food is chewed the surface
increases allowing for a more compete consumption of the
food by the rumen bacteria. The bacteria can multiply at
a greater rate providing more bacteria to pass out of
the reticulum to become the main nutrition source for
the cow. This "cud chewing" process increases the feed
efficiency of the cow decreasing the amount of fed
needed for body maintenance or increasing the
amount of weight gained per pound of feed consumed.
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Saliva
Ruminants produce large quantities of
saliva, estimated amounts for adult cows are in the
range of 100 to 150 liters produced per day. Aside
from its normal lubricating qualities, saliva serves at
least two very important functions in the ruminate
stomach:: (1) Provides the fluid for the fermentation
vat and (2) alkaline buffering - saliva is rich in
bicarbonate, which buffers the large quantity of acid
produced in the rumen and is critical for maintenance of
rumen pH. |
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Rumen problems & care
Normal rumen
pH is 6.5 to 6.8,
Abomasum
is 3.5 to 4 |
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