Submitted to: Proceedings of American Registry of Professional Animal Scientists
Publication Type: Proceedings
Publication Acceptance Date: December 21, 1998
Publication Date: N/A
Technical Abstract: Carbohydrates are an important component in dairy rations that provide the majority of energy for cows, but also comprise the feed fractions which limit intake and digestibility. Because they vary tremendously in nutritive availability and their effects on ruminal function and intake, analysis of carbohydrates is a critical element in ration formulation. Although the terms are often used interchangeably, plant cell walls and neutral detergent fiber (NDF) represent different approaches to carbohydrate classification and analysis. Fiber is a nutritional term that defines the indigestible and slowly digesting fractions of feeds that occupy space in the gastrointestinal tract. The amylase-treated neutral detergent (aNDF) fiber method solves most of the problems associated with fiber analysis and can be a useful tool for ration formulation. The NDF content of feeds when adjusted for differences in filling effect and physical effectiveness can be used to determine the maximum and minimum fiber in dairy rations. It provides an excellent tool for evaluating the fiber, carbohydrate, and energy characteristics of feeds and rations. Because aNDF separates feeds into NDF and NDS (neutral detergent solubles) fractions, it identifies the major differences among feeds and allows them to be described on a single continuum.