Factors Affecting Forage Intake by Range Ruminants: A Review

Variation in voluntary forage intake is undoubtedly the major dietary factor determining level and efficiency of ruminant production. This variation is largest and least predictable for grazing ruminants. Range ruminant productivity and efficiency is relatively low due, in part, to intake limitations; therefore, productivity could probably be increased most by increasing intake. Most available literature points to digestibility and rate of ingesta passage and reticulo-rumen fill as primary mechanisms of intake regulation in range ruminants. Body size and physiological status of ruminants appear to have the largest effect of animal-related factors in governing level of voluntary intake. Kind and amount of supplementation, forage availability, and grazing intensity are major management-controlled variables affecting intake by domestic range ruminants.