Botanical and Nutritive Content of Diets of Cattle and Sheep under Single and Common Use on Mountain Range

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Abstract
A study to determine differences in the botanical composition, nutritive content and digestibility of diets of cattle and sheep grazing singly and in common on sagebrush-grass and aspen ranges was conducted on northern Utah mountain ranges during the summers of 1963 and 1964. Six study areas of each vegetation type were selected and fenced into three enclosures, allowing proportionate amounts of herbage per animal-unit-day grazing to obtain comparable use of preferred forage classes by cattle and sheep. Two of the enclosures were grazed singly by cattle and sheep, and a third enclosure of combined size of the other two was grazed by the animals in common. Experimental animals were equipped with esophageal-fistula cannulae. A 5- to 6-day digestion trial was conducted during each grazing period. Digestibility was determined by the lignin-ratio technique. Cattle preferred grasses, while sheep preferred forbs and browse. Utilization of grasses by both cattle and sheep decreased and preference for browse increased as the season advanced. Utilization of the primary herbage species under common use was found to be, in most instances, intermediate to the single-use values for cattle and sheep. Therefore, it was concluded that if utilization of the primary forage species were allowed to reach the equivalent under single use, additional animal-days of grazing per acre would be realized under common use as compared to single use by either kind of animal. Cattle diets were higher in cellulose, but sheep diets contained more total protein, lignin, other carbohydrates and phosphorus. Sagebrush-grass range yielded diets higher in total protein, lignin and gross energy, but lower in ether extract and the other carbohydrates compared to aspen range. Cattle digested cellulose, ether extract and gross energy better than sheep and had more DE and TDN in their diets. Digestion coefficients for ether extracts, other carbohydrates and gross energy were higher for diets on aspen range. These diets also contained more DE and TDN than diets on sagebrush-grass range. Grazing systems did not significantly influence the digestibility of any nutrient studied, nor did they influence the level of any digestible nutrient. Copyright © 1967. American Society of Animal Science . Copyright 1967 by American Society of Animal Science