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Thesis (M.S.)—University of Nebraska—Lincoln, 1970. Department of Animal Science.


Copyright 1970, the author. Used by permission.


Because of the decrease in arable land in the world and the severe competition for natural proteins by humans and non-ruminants, it becomes necessary that a portion of the natural protein in ruminant diets be replaced with non-protein nitrogen. Urea is commonly used but there are inefficiencies in its utilization by the ruminant. Of the major problems limiting the utilization of urea, the main one is the rapid production of ammonia. The estimate is that urea hydrolysis occurs four times faster than uptake of the liberated ammonia. This results in an eventual loss of nitrogen available for microbial protein synthesis. If the release rate were slower, ruminal ammonia could be converted more efficiently into microbial protein. To accomplish this, attempts have been made to reduce the rate of ammonia production from urea and, thereby, allow for a more efficient utilization of urea-nitrogen.

The objective of the research reported in this thesis was, therefore, to study the effect of (1) incorporation of urea into a compacted starch compound and (2) sulfur-coating of urea on rate of ammonia release, nitrogen retention and ration digestibility in sheep.

Advisor: Walter R. Woods