It is well-documented that endophytes can enhance the resistance of agronomical grasses, such as tall fescue and perennial ryegrass to herbivory. For native grasses, however, the related reports are limited, and the conclusions are variable. Achnatherum sibiricum is a grass native to the Inner Mongolian steppe. This grass is highly infected by endophytes but does not produce detectable endophyt...

unshaded sites in southern USA when exposed to high summer temperatures (Van Santen and Sleper, 1996). The design of agroforestry systems requires a thorough understandNeither orchardgrass nor tall fescue had significant ing of biological interactions that might complement or constrain yield reduction in pots exposed to 50% shade, and orproduction. The objective of this study was to examine eff...

............................................................................................................................ iii ACKNOWLEDGMENTS ........................................................................................................ v CHAPTER 1. GENERAL INTRODUCTION ...................................................................... 1 Thesis Organization .......................

Abstract Fescue toxicosis decreases beef cattle performance in a multitude of ways, including decreased health and immunity. Cattle challenged by fescue are often grazing an environment favorable for development gastrointestinal nematodes (GIN). Interactions parasite challenge may result further economic losses. Many producers treat animals regularly GIN parasites with little insight on necessi...

The predominant cool-season forage in the southeastern United States is the tall fescue cultivar Kentucky 31 (KY31). Kentucky 31 possesses an endophyte (), which produces a family of toxins called ergot alkaloids. These toxins negatively affect the physiology of animals on consumption and result in the syndrome known as fescue toxicosis. Currently, the United States annually produces approximat...

Two studies separated effects of dietary ergot alkaloids from effects of feed intake or ambient temperature on respiration rate (RR), heart rate (HR), surface temperature (ST), rectal temperature (RT), blood pressure (BP), serum hormone, and plasma metabolite concentrations in beef steers. The balanced, single reversal design for each experiment used 8 beef steers fed tall fescue seed [2.5 g/kg...