Urea is used as most common non-protein nitrogen feed source for ruminants, which contains 46.7 percent of nitrogen. It is fed as a replacement for a part of the protein in a ration. The ability of microorganisms present in the rumen of ruminants, use of feeding urea reduces the need for imported protein supplements with no deleterious effects on the animal. Treating with urea is based upon its transformation into ammonia. The amount of urea included in concentrate mixtures for cattle or sheep should not exceed 3 percent and usually the addition of 1 to 1.5 percent will prove adequate. Favorable results have been recorded with ensiling urea to green maize at the rate of 0.5 percent of the weight of the fresh forage. Urea feeding has several advantageous effects on body weight, growth rate, and higher milk yields, even under adverse conditions. Source of readily available carbohydrates, frequency and level of feeding urea, proper mixing, solubility of proteins, adequate supply of minerals, etc. are the factors affecting urea utilization in ruminants. Excess level of urea feeding may develop a problem of Urea toxicity (poisoning), due to poor mixing of feed or to errors in calculating the amount of urea to add to the ration. Methods are needed to reduce the fast rate of urea breakdown in the rumen to ensure slow absorption. Research on slow-release pellets or on new compounds that would allow urea to be released in about five hours would safeguard its use.
This review paper was selected in 2010 Alltech Young Scientist Competition as First Position Local winner from Nepal and the author was awarded with Certificate and Medal from Alltech Young Scientist Program.
To download complete paper UREA AS A NON-PROTEIN NITROGEN SOURCES FOR RUMINANTS