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Physiological Changes Associated With Pregnant Or Nonpregnant Mares Grazing Pastures Of Orchardgrass-Bluegrass, Kentucky 31 Tall Fescue Infected With Epichloë Coenophiala, Or Kyfa9821 Tall Fescue Infected With The Novel Endophyte Ar584, Victoria A. Taylor

Theses and Dissertations--Veterinary Science

Kentucky 31 tall fescue (KY31) infected with the common toxic endophyte strains of Epichloё coenophiala produces toxic alkaloids that improve plant vigor, but cause numerous adverse effects in grazing animals. Researchers developed a variety of KY31 containing an alternative strain of E. coenophiala, termed novel endophyte (NE). Adverse health effects in mares have not been evaluated.

Experiments in this thesis tested the hypothesis that the NE pasture does not cause adverse effects typically associated with KY31. Specific aims were to: 1) compare forage ergovaline concentrations between KY31 vs NE pastures; 2) evaluate palmar artery diameters in mares grazing KY31, …

Ingestion Of Endophyte-Infected Tall Fescue Seed Induces Peripheral Vasoconstriction But Does Not Affect Cyclicity In Non-Pregnant Mares, And A Population Of Biogenic Amine Receptors Relative To Vasoconstriction Is Identified, Daniel Andrew Hestad

Theses and Dissertations--Veterinary Science

Three experiments were conducted to explore the effect of fescue toxicosis on vasoconstriction and various parameters of the estrous cycle. In the experiment of Chapter 3, a 2x2 crossover experimental design with repeated measures was implemented to test whether the ingestion of endophyte-infected tall fescue seed would alter blood hormone concentrations of prolactin, progesterone, and estradiol, interovulatory intervals, and corpus luteum blood flow. Also, Doppler ultrasonography was used to assess whether palmar artery and palmar vein lumen diameter, area, circumference, and resistivity index could be altered by the ingestion of endophyte-infected tall fescue seed. Ingestion of endophyte-infected tall fescue seed …