Using the unique degradation ratio system (DRS) as an alternative method for feed evaluation and diet formulation: A review

Recently obtained information on applications of the unique degradation ratio system (DRS) as an alternative method for feed evaluation and diet formulation is reviewed, in relation to optimum rumen fermentation and nutrient utilization and availability. The DRS ratio values show the balance between potentially microbial protein synthesis from rumen degradable crude protein and that potentially from the energy extracted during anaerobic fermentation in the rumen. In modeling feed evaluation and diet formulation, the degradation ratios can be used in assisting to detect effects of feed processing and optimize the composition of ruminant diets. Unfortunately, few researchers provide such crucial ratio data when they studied rumen degradation characteristics of a feed or diet mainly due to lack of knowledge of the DRS system. The emphasis of this article is on: (i) systematic introduction of the DRS system; and (ii) prediction the optimal rumen fermentation using the DRS system. The information described in this article may give better insight into the principal, computation and applications of the DRS system for feed and diet evaluation. A focus of the article is on evaluation of the DRS system as an alternative new approach to establishment of a feed evaluation system that more accurately accounts for feed digestive processes in the ruminant on a quantitative basis.