Methods to study degradation of ruminant feeds

Ruman degradation is crucial in the supply of dietary nutrients to meet the nutrient demands of the anaerobic microbes and body tissues of ruminant animals. Therefore, it is essential to study the dynamics of rumen degradation of various feeds before their potential use to formulate nutritious diets for ruminant animals. Amongst many methods that have been used in the past, the in sacco method has been the most effective method to study rumen degradation. However, this method is undesirable due to its implications for animal welfare and costs. While many in vitro methods have been tested as possible alternatives to the in sacco method to study rumen degradation of feeds, they were unable to remove the need to use fistulated animals to obtain rumen fluid. Although solubility, enzyme- and faeces-based in vitro methods do not require rumen fluid, they still need data from either the in sacco method or the rumen fluid-based in vitro methods for comparison and validation. Therefore, there is a need to develop in vitro methods that do not require the need to surgically modify ruminants to obtain rumen fluid to study rumen degradation. We review the potentials and problems associated with the existing methods to study rumen degradation and their implications for the animal industry in different situations.