The Effect of Range Condition and Season of Grazing on the Amount and Quality of the Diet Selected by Grazing Steers

Adequate knowledge of the nutrition of grazing animals depends on accurate measurement of both intake and nutritional value of the forage being consumed. Cattle grazing native grasslands select their diet from a variety of plants which are continually changing in palatability, digestibility and chemical composition. The result of these changes may be inadequate nutrition for optimum animal production on a sustained basis. As forages mature, overgrazing occurs or with the onset of drought the incidence of inadequate nutrition of range livestock increases. Many workers agree that sampling from the esophageal fistula is the best method of evaluating the nutritional value of the forage being consumed by grazing animals. However, there is much less agreement between researchers as to the best method of measuring forage intake. Recent work by Hyder et al. suggests that the water-intake method of estimating forage intake is less tedious and expensive and possibly as accurate as more commonly used methods of estimating forage intake. This study was conducted to: 1. Determine the effect of range condition and season on the botanical composition, chemical composition and digestibility of the diet selected by esophageal fistulated yearling steers grazing small pastures at similar grazing pressures. 2. Compare different methods for measuring forage intake of grazing steers. 3. Compare forage intake and fecal composition of esophageal fistulated steers carrying fecal bags with forage intake and fecal composition of normal unbagged steers