Urea for beef cattle and sheep

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Urea for Beef Cattle and Sheep I
What Is Urea?
Urea is a nitrogen compound that can be used to
meet a part of the protein requirement of beef cattle
and sheep. Found in many plants, urea is a normal
end product of protein metabolism in mammals. A
part of the urea produced in the animal body is returned to the digestive tract by the saliva. The
remainder of the urea is passed off in the urine as
waste.
Urea, as used in commercial beef cattle and sheep
protein supplements, is a colorless, odorless compound manufactured from such common raw materials as coal, air, and water. Thousands of tons are
produced annually for use in industry and agriculture.
The main agricultural uses are as fertilizer and in feeds.
Pure urea contains 46.7 percent nitrogen. One pound
of pure urea furnishes as much nitrogen as 2.c)2
pounds of protein (protein equivalent of 292 percent).
The feed grade urea has other ingredients to prevent caking and lumping. This material lowers the
protein equivalent to 262 or 281 percent.
Utilization
Nutritionally, urea is like protein only in that it
contains nitrogen. It cannot be used to advantage in
feeds for animals with simple stomachs, such as swine
and poultry; but it can be used by beef cattle and
sheep because these animals have a large rumen or
paunch where feed undergoes fermentation. Rumen
micro-organisms have the unique ability to convert
urea to protein. Utilization of urea requires a source
of readily available energy. This is best supplied by
starch, which is in large quantities in cereal grains.
Sugars and cellulose are inferior to starch for maximum urea utilization. Sugars pass out of the rumen too
rapidly and cellulose is not broken down fast enough
to supply energy compounds necessary for conversion of urea to protein. Molasses may be beneficial
for urea utilization, especially if the ration is low in
starch. A ration may need supplemental minerals
when  part  of the  protein has been replaced with
urea. This is because of the removal of part of
the cottonseed meal or other mineral-containing
supplement.
A Protein Replacement
Urea is fed to beef cattle and sheep as a replacement
for a part of the protein in the ration. Whether it is
economical depends on its cost in relation to other
high-protein foods. At a protein equivalent of 281
percent. 11.8 pounds of urea and 88.2 pounds of
milo grain (9 percent protein) are equal in protein and
energy value to 100 pounds of 41-percent-protein
cottonseed meal or similar supplement.
To determine the cost of the urea-milo mixture,
use current prices per ton for both ingredients. Add
to this the current charge for grinding, mixing, and
pelleting (probably S10 to SI5 per ton). This will
give you the cost per ton, which may be compared
directly to the cost of 41-percent-protein cottonseed
meal or a similar supplement. The cheaper is more
economical, because results should be similar.
Toxicity
Urea can be toxic when fed at too high levels or
when recommended levels are poorly mixed. When
fed at levels greater than the capacity of the rumen
micro-organisms to convert it to protein, it is absorbed into the bloodstream as ammonia, which is
toxic at high levels. Most instances of urea poisoning
are due to poor mixing or to errors in the amount of
urea to add to the ration. There is no danger from
recommended levels o\~ urea properly mixed and fed
according to directions. If toxicity occurs, an emergency measure, while awaiting arrival of a veterinarian,
is drenching with one gallon of vinegar. The vinegar
lowers the rumen pH and neutralizes ammonia.
Symptoms of urea toxicity include uneasiness,
tremors, excess salivation, rapid breathing, unco-
ordination, bloat, and tetany. Tetany (muscular
spasm) is the last symptom observed before death
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