Eructation
In the animal,
very large quantities of gas, mostly those of carbon dioxide as well as methane
are produced in the rumen. The production amounts of these gases are up to 30
to 50 quarts per hour and must be removed; otherwise bloating will occurs in
the animal. Under normal conditions, distension from gas formation causes the animal
(cow) to belch and eliminate the gas from the digestive track.
Rumination
In rumination,
a cow can spend as much as 35 to 40 percent of each day ruminating by means of
chewing its cud. The actual amount of time spent by the animal ruminating
varies from very little, that is when grain or finely ground rations are fed to
several hours as well as when long hay is been fed to the animal. Mature cattle
spend little time chewing during the time of eating. During rest periods, feed
boluses are then regurgitated for re-chewing to reduce the particle size and
for resalivation. Feed is more readily digested by rumen microbes as the particle
size is reduced.
The rumen and reticulum motility
The rumen in
its nature is always contracting and mobile. Healthy animal (cows) will have
one to two rumen contractions in the space of one minute. The contractions mix
the rumen contents, bring microbes in, then contact with new feed stuffs,
reduce flotation of solids, and move the materials out of the rumen. Lack of or
a decrease in frequency of rumen movements is one way of diagnosing of sick
animals (cow).
Production of saliva
In the
production of saliva by the animal, as much as 50 to 80 quarts of saliva can be
produced by the salivary glands and then added to the rumen each day. Saliva
provides liquid for the microbial population, recirculates nitrogen and
minerals, and buffers the rumen. Saliva is the major buffer for helping to
maintain a rumen pH between 6.2 and 6.8 for optimum digestion of forages and
feedstuffs by the animal.
Vomiting
Vomiting in
cattle is usually not common and therefore sometimes valuable, Cattle rarely
vomit. Occasionally certain feeds giving to the animal will induce vomiting. Most
pasture plants, usually that of weeds, contain alkaloids that can lead to the
problem of the animal vomiting. In circumstances were this condition persist, a
veterinarian should be consulted to look into it and ascertain the problem.
Digestion of energy feeds in the
rumen
In digestion
of energy feeds in the rumen, the simple and complex carbohydrates (fiber) are
digested by rumen microbes and then converted into volatile fatty acids. The
volatile fatty acids, which consist mainly of acetic, propionic, and butyric
acids, are the primary energy source for ruminants. When large amounts of
forage are fed to the animal, the formation of acetic acid predominates with
lesser amounts of propionic and butyric acids occurring. However, when grain
feeding is increased or when finely ground forages are fed to the animal, the
proportion of acetic acid may decrease to fourty percent, while the amount of
propionic acid may also increase to fourty percent. Such a change in volatile
fatty acid production generally is associated with a reduction in milk fat
test.
Approximately
thirty to fifty percent of the cellulose and hemicellulose is digested in the
rumen by the microbial population. Sixty percent or more of the starch is
degraded, depending on the amount fed and how fast the ingested materials move
through the rumen. Most sugars are hundred percent digested within the rumen
track.
The volatile
fatty acids are absorbed from the rumen, the move into the blood stream and
transported to body tissues, including the udder, where they are used as
sources of energy for maintenance, growth, reproduction, and milk production.
The cow derives fifty to seventy percent of its energy from the volatile fatty
acids which is produced in the rumen track.
Vitamin synthesis
The rumen
micro-organisms produce all of the B vitamins and vitamin K. The vitamin
synthesis in the rumen is sufficient and enough for growth and maintenance.
Under most conditions, cattle with functioning rumens do not require
supplemental B vitamins or vitamin K in their diet. Niacin (B3) and thiamine
(B1) may be needed under stress conditions of the animal to reduce or avert the
stress.
Fat digestion
Some of the
digestion and absorption of fat in the animal occurs in the small intestine.
Rumen micro-organisms change unsaturated fatty acids to saturated acids through
the addition of hydrogen molecules. However, more saturated fat is absorbed by
cows than by simple-stomach animals. Feeding large quantities of unsaturated
fatty acids can lead to toxic to rumen bacteria; depress fiber digestion and
lower rumen pH as well.
Digestive System of calf
During the
first few weeks of life of the calf, the rumen, reticulum, and omasum are in
the undeveloped stage. In contrast to the mature cow, in the calf, the abomasum
is the largest compartment of the stomach at this stage of life, the rumen is the
nonfunctional and some feeds digested by the adult cannot be used by the calf.
During nursing or feeding from a bucket, milk bypasses the rumen via the
esophageal groove and passes directly into its abomasum. Reflex action closes
the groove of the animal to form a tube-like structure which prevents milk or
milk replacer from entering the rumen. When milk is consumed very rapidly, some
may over flow into the rumen track.
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