Forage intake of cattle as affected by stocking pressure

Abstract

A series of trials was conducted in April, July, and September, 1977 to examine the effect of level of stocking pressure on organic matter intake and on the botanical and chemical composition of cattle diets. Levels of stocking pressure studied were 10, 20, 40, and 50 kg forage allowed per animal-unit per day (kg/AU/da) for a 14-da trial. Herbaceous forage availability was measured before, during the middle and immediately after each stocking pressure trial. Botanical and chemical com position of cattle diets was obtained from esophageally fistulated cows at the beginning, middle and end of each trial. Organic matter intake by cattle grazing the four levels of stocking pressure was estimated by the fecal output: indigestibility ratio technique, with fecal production being measured by total fecal collection and digestible organic matter being estimated by in-vitro technique, lignin ratio, and acid-insoluble ash ratio. Total standing crop was significantly reduced for the 10 and 20 kg/AU/da stocking pressure levels when compared to the 40 and 50 kg/AU/da levels. Forage availability declined steadily during the trials, with standing crop being significantly less at the end of a trial than at the beginning or middle of a trial. Average forage disappearance per animal-unit per day was 8 .5 , 12.0, 12.7, and 16.3 kg/AU/da for the 10, 20, 40, and 50 kg/AU/da treatments, respectively. The overall forage disappearance of 8.5 kg/AU/da for the 10 kg/AU/da treatment closely approximated the average intake of 8.4 kg/AU/da for this level of stocking pressure..