• January 19th, 2019
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The role of urea in livestock nutrition

Erastus Ngaruka

The   words   urea   (English),   “ureum”   (Afrikaans),   “oiriuma” (Otjiherero) are common to many  farmers  when  it  comes  to livestock lick supplementation. However, the use or role of urea is widely not well understood, apart from it being  labelled as a risk  to  livestock.   

In  livestock  nutrition  explanations,  urea  is  a non-protein nitrogen compound that is converted into protein in the  rumen  of  a  ruminant  animal  (cattle,  sheep, goats). These  animals’  digestive  system  is  comprised  of  four  stomach compartments, the rumen, abomasum, omasum, and the reticulum.

The  rumen  is  the  principal  compartment  for  fermentation  of  ingested  feed.  This fermentation  or  breakdown  of  food  is  performed  by  the  microorganisms  (bacteria) living in the rumen called “rumen microbes” or simply rumen bacteria. The efficiency of  fermentation  in  the  rumen  depends  on  the  efficiency  of  the  microbes,  and  the efficiency of the microbes depend on the availability of urea, and the effective use of urea  depend  on  the  population  of  microbes  and  the  energy  content  of  the  feed amongst others.

When  urea  enters  the  rumen,  the  microbes  break  it  down  to  release  ammonia  (a gas) which they then convert into protein, known as “microbial protein” which the microbes use as their food to grow and multiply, thus enhancing their performance in  terms  of  digestion.  This  is  why  urea  is  needed  during  the  dry  season  to  help animals digest the dry forage materials effectively.  Much of the urea in licks/feed is utilized by the microbes than by the animal’s body itself.

Why and when is urea a risk?
Urea  becomes  a  problem  when  the  ammonia  released  by  urea  is  in  excess  and cannot all be converted into protein by the microbes. This ammonia is transported to the liver for detoxing and excretion (removed) from the body via urine.   

When this ammonia  is  too  much  for  the  liver,  then  toxicity  takes  place.  This  happens  when there is insufficient fermentable energy in the feed to help the breakdown of urea or when the feed contains a significantly high crude protein already. Therefore it is very important to feed the correct amount of urea to animals and to provide or mix urea-containing  lick  supplements  according  to  instructions,  and  also  to  consult  animal nutritionist or livestock experts. Most of the winter lick supplements contain urea, e.g. dryveld  concentrate,  cattle  lick  40,  cattle  mix  415,  and  bush  improver,  amongst others.

On the other hand, urea is also a problem when not carefully handled at farm. When urea is not thoroughly mixed, has formed lumps, the animal is at risk of ingesting too much at an instant. A tablespoon of urea can be potent enough for the animal. Urea dissolves easily in water, thus, if the animal drinks such water, it will be poisoned. It is therefore advisable to avoid giving urea supplements when it is raining, and not to expose the lick trough to water accumulation.
Signs of urea poisoning and remedial actions

The onset of  symptoms after ingestion of  urea can be from 30 minutes  to three hours depending   on   the   amount   ingested   amongst   others.   The   symptoms   of   urea poisoning include muscle twitching, frothy salivation, incoordination, spasms, bloat, abdominal pain, rapid breathing and weakness amongst others. The most basic and available  remedies  for  treating  urea  poisoning  is  water  and  vinegar.  For  cattle,  a mixture of vinegar (750ml) and one litre of water, and for sheep and goats a half bottle of vinegar and half a litre of water given orally.
Lastly, provide the right supplements at the right time to the right animal in the right amount.  Supervise  the  mixing  of  licks  at  the  farm,  and  always  observe  animals around the lick and water troughs. Have a first aid tool box at the farm, and report any abnormalities immediately.

* Erastus Ngaruka is Technical Officer within Agribank’s Agri Advisory Services Division. 

New Era Reporter
2018-10-26 10:11:10 2 months ago

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