The objective was to determine the effect of forage quality on apparent total tract digestibility and ruminal fermentation in cattle versus sheep. Five yearling English crossbred (Hereford × Angus) steers (440.4 ± 35.6 kg of initial BW) and 5 yearling whiteface (Rambouillet × Columbia × Debouillet) wethers (44.4 ± 4.6 kg of initial BW), each fitted with a ruminal cannula, were randomly assigned...

Top-down effects of predators on prey behavior and population dynamics have been extensively studied. However, some populations of very large herbivores appear to be regulated primarily from the bottom up. Given the importance of food resources to these large herbivores, it is reasonable to expect that forage heterogeneity (variation in quality and quantity) affects individual and group behavio...

The objective was to determine the effect of forage quality on apparent total tract digestibility and ruminal fermentation in cattle versus sheep. Five yearling English crossbred (Hereford × Angus) steers (440.4 ± 35.6 kg of initial BW) and 5 yearling whiteface (Rambouillet × Columbia × Debouillet) wethers (44.4 ± 4.6 kg of initial BW), each fitted with a ruminal cannula, were randomly assigned...

Two experiments were conducted to quantify the impact on forage use and performance of varying supplementation frequency of cattle consuming forage diets across a range of frequencies. In both experiments, a common supplement was used that contained a relatively high concentration of CP (43%) and was fed at the following frequencies: 1) 2 d/wk; 2) 3 d/wk; 3) 5 d/wk; and 4) 7 d/wk. In Exp. 1, 12...

A nationally accepted standard hay test for alfalfa hay has included measurement of Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), Dry Matter (DM) and Crude Protein (CP). Total Digestible Nutrients (TDN) has typically been calculated directly from a fiber measurement, usually ADF. However, this is likely to change. While there are a range of points of view on forage testing, it is l...

Two explanations exist for the evolutionary origin of grouping in primary consumers: reduction of individual predation risk and resource-mediated aggregation. While several studies have assessed relationships between aggregation and predation risk, few studies have examined the circumstances under which resource-mediated aggregation can lead to stable group formation. Using a model, we examined...

field trials. The use of row-column analysis or neighbor analysis has been shown to increase the precision of a Spatial analyses of yield trials are a powerful method of adjusting large number of grain yield trials (Cullis and Gleeson, treatment means for spatial variation and improving statistical precision of mean estimation. Because yield trials are typically repeated 1989; Cullis and Gleeso...

Abstract. Rangelands are mainly used for grazing the livestock in Iran, it is essential to specify grazing suitability of rangelands in each region of country, so that it may improve the management policies and approaches for planning and designing current and future plans. The aim of this research was to determine the rangeland suitability for sheep grazing in the watershed of Sadegh Abad, Ker...

Some of the most compelling examples of ecological responses to climate change are elevational range shifts of individual species, which have been observed throughout the world. A growing body of evidence, however, suggests substantial mediation of simple range shifts due to climate change by other limiting factors. Understanding limiting factors for a species within different contexts, therefo...

Conservation of migration requires information on behavior and environmental determinants. The spatial distribution of forage resources, which migration exploits, often are altered and may have subtle, unintended consequences. Supplemental feeding is a common management practice, particularly for ungulates in North America and Europe, and carryover effects on behavior of this anthropogenic mani...