Abstract
Protein is an important nutrient which provides amino acids to ruminants to satisfy their maintenance and
production demand. Oegradability of dietary protein affects the rumen fermentation which leads to influence the
efficiency of absorbed nutrients and availability of amounts and proportions of amino acids to ruminants. The dry
matter intake (OMI) is increased with increase in ruminally undegradable protein (RUP) in the diet. However, OMI
is also increased with increase in ruminally degradable protein (ROP) in diets which are deficient in ROP. The
increase in OMI with increase in ROP is due to the increased ruminal NH3-N concentration because insufficient
ruminal NH
3
-N depress microbial function and thereby limits intake. Ruminal pH is reduced with supplementation
of ROP and this reduction in pH is due to higher bacterial activity, fermentation and volatile fatty acid production.
Higher dietary ROP results in increased microbial count in ruminants. The increased microbial count with
increasing dietary ROP level is attributed to increased concentrations of ruminal NH3-N, amino acids, peptides, or
branched chain volatile fatty acids required for microbial growth. Ory matter (OM) digestibility is increased with
increasing the level of dietary ROP. Increased OM digestibility with increasing level of ROP is attributed to
increased ruminal NH3
-N concentration resulting increased ruminal microbial activity. Milk yield and fat correct
milk is increased with increasing the level of RUP in the diet of ruminants. The increase in milk yield in lactating
ruminants with increasing the dietary level of RUP is due to an increase in OMI as well as the increased supply of
metabolizable protein. Ration containing improper proportion of ROP and RUP not only impedes the productive
potential of the animal but also aggravates some metabolic changes which ultimately give birth to decreased OMI,
lowered digestibility and poor energy utilization by the animal.
