Thesis (Ph. D.)--Oregon State University, 1974. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 1973. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Graduation date: 1994

The objectives of this study were to document the negative effects of endophyte-infected fescue consumption on cow physiological responses after stress challenge and to assess the ability of blessed thistle to ameliorate these responses. Twenty -seven Angus crossbred cows approximately 5-7 years of age and a body weight of (634 ± 80 kg) were equally divided into 3 treatments. Each treatment was divided into 3 replicates, leaving pens of 3 cows per treatment replicate. Each pen was balanced for initial body weight and low age. Each experimental group was randomly assigned to one of three replicates and one of three treatment dietary regimens: control/endophyte-free (EF) fescue, endophyte-infected (EI) fescue, endophyte-infected fescue + blessed thistle supplementation (EIBT). Ergovaline, one alkaloid compound thought to be deleterious in the endophyte-infected fescue metabolites was detected in EI seed analysis performed before the trial commenced. Endophyte-free seed samples were negative for total ergot alkaloids. No treatment interaction was observed for heart rate, body temperature, prolactin and urinary alkaloid analysis rate (P >0.05). A replicate interaction was observed for prolactin (P <0.05). There was an effect of stress point between before and after samples taken on D-1 and D 29 on body temperature, heart rate and cortisol (P <0.05). Results suggest treatments were ineffectual at inducing symptoms of fescue toxicosis. The full capability of blessed thistle to ameliorate symptoms of fescue toxicosis may not be fully represented in this study. Further research and knowledge into the mechanism by which fescue toxicosis impacts health and productivity of livestock is needed to develop sustainable treatment regimens.

Fescue toxicosis is a condition that afflicts livestock grazing endophyte-infected tall fescue and is particularly detrimental to pregnant mares. A two year evaluation study of a novel endophtye-infected cultivar, AGRFA-144 (A-144), did not induce fescue toxicosis in late-term pregnant mares. All mares delivered viable foals except in E+ group which had two viable foals, one stillborn-dystocia and one compromised foal which was euthanized at 72 h pp. Serum P4 concentrations were similar among A-144, NE+, and E- mares (p>0.05). Foal BW and foal/placental weight ratios were similar for A-144, NE+, and E- (p>0.05). Foal serum P4 was similar on 1 d and 2 d in all groups, but was lower (p = 0.049) in the A-144 group than the E- foals on day 0. Neutrophil/lymphocyte ratios were similar (~5:1) in all foals on d 0 and 2. IgG values were similar (p>0.05) among A-144, NE+, and E-.

Accurate taxonomy is essential to preservation and management of native grasses. Four problems in fescue taxonomy were investigated: the identity of the native fescue that dominates western Oregon and Washington prairies, the relationship of native Festuca roemeri to closely related grasses, the status of F. howellii and F. washingtonica, and fescue identification. The cespitose fine-leaved fescue that dominates prairies in western Oregon and Washington had previously been identified as F. rubra. Two fescues were found to dominate these habitats, one introduced F. rubra var. commutata, and the other native F. roemeri. The two differed in isozymes and subtle morphological traits. Isozymes, flow cytometry of DNA, and leaf anatomy clarified relationships among F. idahoensis, F. roemeri. and the northwest California fescue that shares characters with both of them. Isozyme band patterns divided them into two groups; F. roemeri and a mixture of populations of F. idahoensis and the northwest California fescue. All three fescues were tetraploid. All three fescues were distinguished using leaf anatomy. Festuca roemeri and the northwest California fescue shared leaves elliptic to obovate in cross section and usually having three sclerenchyma bands, at margins and midrib; F. idahoensis had leaves round to hexagonal in cross section, with five or more sclerenchyma bands, Festuca idahoensis and the northwest California fescue had numerous long adaxial leaf hairs; F. roemeri had few and short adaxial hairs. Leaf shape was phenotypically plastic in F. roemeri and the northwest California fescue, but constant in F. idahoensis. Leaf sclerenchyma development was greater in the field than greenhouse for all three fescues. The northwest California fescue was recognized as F. roemeri var. klamathensis B. L. Wilson fined. Morphometric analysis of F. howellii and F. washingtonica revealed that the two are distinct taxa. Festuca washingtonica appeared to be a rare species endemic to lightly grazed and ungrazed areas of eastern Washington. The F. howellii holotype was conspecific with F. elmeri, not F. viridula as previously thought. Because F. howellii is an earlier synonym, F. elineri must now be called F. howellii. Identification keys were provided for identifying fertile or sterile fescues and ryegrasses of the Pacific coast states. / Graduation date: 1999

Thesis (M.S.)--California Polytechnic State University, 2010. / Title from PDF title page; viewed on March 2, 2010. Major professor: Terry Vassey, Ph.D. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Agriculture." "January 2010." Includes bibliographical references (p. 32-35).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 76-78). Also available via the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on May 7, 2009) Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.