Question

describe the danger of urea poses to livestock.suggest possible precautions that may limits this possible dagerous effects.

Answer 1

Feed-grade urea can be an
effective source of protein in
beef cattle diets.
The high cost of feed grains and
many high-protein grains may
make the use of urea as a
protein source very cost-effective
in many cattle diets. Several
issues must be considered,
though, to make its use most
effective.
Urea is a non-protein nitrogen
compound. That is, the nitrogen
portion of urea is used as the
building block for the production
of protein by rumen microbes.
Most urea contains about 45%
nitrogen, and protein contains
16% nitrogen. Therefore, when
urea is converted to protein, the
crude protein equivalent value of
urea is about 281%. It must be
recalled that urea contains no
other useful feed components
such as energy, minerals, or
vitamins.
Cattle and other ruminants
convert urea to protein through
the production of ammonia and
carbon dioxide. Sewell (1993)
points out the ammonia that is
released from urea can go two
pathways in the animal. The first
location is in the production of
microbial protein, and the
second is the liver where it is
de toxified and excreted in the
urine.
When too much ammonia
escapes the rumen because the
microbes are not able to utilize
enough of it for protein, the
capacity of the liver for excretion
can be overwhelmed and a
toxicity can occur. It is vitally
important that the right level of
urea is fed and that there will be
sufficient bacterial action to
produce protein. The level of
bacterial action will be
determined by the urea
fermentation potential (UFP) of
the total ration. When there is a
higher level of fermentable
energy available in the feed than
what is required by the rumen to
convert the ammonia in the feed
to protein, the feed will have a
positive UFP. If there is
insufficient energy in the feed, or
the feed already contains
significant crude protein, the UFP
will be negative. Thus, corn will
have a positive UFP and fescue
hay and soybean meal will both
have a negative UFP. These
results indicate feedlot rations
high in energy will usually have
the best potential for the use of
urea as a protein source.
However, combining several
feeds that result in the dilution of
urea as a protein source with
other feeds can result in the
formulation of a good protein
supplement for many classes of
cattle on high energy diets.
Precautions for Feeding Urea
As previously shown, urea can be
harmful to cattle if the proper
precautions are not taken to
insure success. These
precautions include:
Formulate diets precisely
with feed components with
known energy and crude
protein values from
labora tory analysis.
Use urea to provide no
more than one-third of the
total protein requirement in
the ration.
Feed the ration at least
twice daily to prevent an
ammonia overload.
Weigh all feed components
precisely and make sure the
urea is mixed completely
and uniformly in the ration.
Do not start feeder cattle on
diets with urea. Rather, use
plant proteins in starting
rations and then convert to
urea-containing rations
after 30 days of feeding.
Cattle will often have a
period of lower intake and
lower weight gains during
initial feeding of urea-
containing rations.
Urea contains only nitrogen
for protein, so mineral,
vitamin, and energy values
should be adjusted with
other diet components.
Higher rumen-bypass
proteins such as distillers
grains (where the more of
the protein is absorbed in
the lower gut and outside
the rumen) are
complementary to urea in
rations.