Forage Quality of Colorado Pastures

Abstract

Irrigated pastures located throughout Colorado were evaluated for quality during the 1974 and 1975 growing seasons. The locations represent the diverse climatic and soil conditions found throughout the state. Twelve chemical components were evaluated from each pasture sample obtained over a 5-month period for both years. The relationships of the various chemical components to each other, to time of sampling, and in particular to in vitro digestible dry matter (IVDDM) were determined. Crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose, cellulose, lignin, silica, IVDDM, calcium, and magnesium showed significant changes during the growing seasons of both years while phosphorus and potassium did not. Acid detergent fiber and silica were shown to have significant positive correlation with time of sampling while crude protein and IVDDM had significant negative correlations during both growing seasons. The best predicators of IVDDM in regression analyses were acid detergent fiber, time of sampling, and hemicellulose. The acid detergent fiber concentration accounted for 60% of the variation in digestibility. The time of sampling and the percentages of acid detergent fiber and hemicellulose provided a reliable estimate of digestibility of irrigated pastures in Colorado.