Fistulation in cattle and use of the rumen degradation technique for feed analysis

Abstract

Nutritional quality of feeds or ingredients used to feed ruminants depends on the level of intake, rumen degradability, digestibility, nutrient concentration, and the efficiency with which these can be metabolized and used. Once feed is ingested, degradability refers to the amount of feed that disappears in the rumen due to the action of the microorganisms. Rumen degradation is crucial in the supply of dietary nutrients to meet nutrient demands of microorganisms and body tissues of animals. Therefore, it is essential to study the dynamics of rumen degradation of 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 to study rumen degradation. However, this method is nowadays used less frequently due to its implications for animal welfare. While many in vitro methods have been tested as possible alternatives to the in sacco method, they were unable to remove the need to use fistulated animals to obtain rumen fluid. Rumen cannulation can be done on a healthy animal currently in the herd with minimal expense. The surgery is not more difficult than most other routine surgical procedures performed by veterinarians. A cannulated animal also provides a long-term, readily available source of rumen content that can be used to transfaunate herd mates that have suffered various digestive upsets. The objective of this work is to present, in a summarized way, the different steps in the fistulation of a cow, and to detail the use of the in vivo or in sacco technique to determine ruminal degradability of feeds or ingredients.