Thesis (Ph. D.)--University of Florida, 1974. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 108-117).

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Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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In vitro embryo production has vastly improved over the past decade through the study of the in vivo environment and the metabolic requirements of embryos. In contrast, in vitro oocyte maturation ( IVM ) culture conditions have remained relatively unchanged and are suboptimal. The aim of this thesis was to create improved systems for bovine IVM by studying the metabolic profiles and requirements of intact cumulus oocyte complexes ( COCs ) during IVM and determining the ion and energy substrate composition of bovine follicular fluid ( FF ). Glucose, pyruvate and oxygen consumption of bovine COCs increased 2 - fold over the 24 h IVM period, with glucose being the preferred energy substrate. While initially the majority of glucose consumed by COCs is metabolised via glycolysis ( Llactate production ), a considerable proportion of glucose is used as a substrate for extracellular matrix ( ECM ) synthesis towards the end of IVM. Glucosamine ( an intermediate substrate of hyaluronic acid ) supplementation of IVM media lead to decreased glucose consumption and incorporation into ECM during FSH - stimulated expansion. Biochemical analyses of bovine FF demonstrated that the concentration of some ions and energy substrates varied with follicle size. Although follicular glucose concentrations increased with follicle size, levels were ~ 2 - fold lower than that found in Tissue Culture Medium ( TCM199 ), the most commonly employed medium for bovine IVM. Synthetic Follicular Fluid Medium ( SFFM ) was created, based on the FF data and also contained glucosamine. Two different glucose concentrations were examined, 2.3 mM glucose to represent physiological concentrations and 5.6 mM glucose, the same concentration as is in TCM199. Culturing COCs in different glucose concentrations manipulated the completion of nuclear maturation and this was dependant on concentration, gonadotrophin supplementation and the timing of media changes, demonstrating the importance of this substrate to meiotic competence. Although glucosamine had no effect on oocyte nuclear maturation, supplementation during IVM led to a dose - dependent decrease in blastocyst rates. The detrimental effects of glucosamine manifested during early cleavage and were associated with a 0.6 - fold decrease in protein synthesis levels within the oocyte compared to oocytes cultured in media with no glucosamine, suggesting a detrimental effect on developmental competence. Interestingly oocytes cultured in media containing glucosamine and EGF had significantly higher protein synthesis compared to the control group. The biochemical profiles of COCs during IVM and FF were determined and used to create new media that allowed manipulation of oocyte nuclear maturation but compromised cytoplasmic maturation. Further research is required to optimise SFFM and to investigate the detrimental effects of glucosamine on developmental competence. / Thesis (Ph.D.)--Medical School, 2004.

Vita. / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries

This study was conducted to determine the relationships among the linear type traits of rump angle, rump width, rump length, rear legs side view, rear legs position, rear legs rear view, tailhead, vulva angle, mobility, pasterns, foot angle, and toes with reproductive performance (days open and times bred) in Holstein cows and to develop indices to predict reproductive performance from mathematical functions of the anatomical traits. Two trials were conducted. The first trial involved 7630 registered Holstein cows from Oregon and California. The regression analysis (R²) showed only 1.1% of the variability of times bred and 1.3% of the variability of days open was accounted for by the rump and rear leg type traits. In the second trial, 8155 Holstein cows, both registered and grade, were analyzed using the linear type traits of rump angle, rump width, rear legs side view, rear legs position, rear legs rear view and foot angle.. Grade and registered cows were analyzed separately to determine if differences in management between them would be reflected in the statistical analysis. Evaluator, lactation number (parity), season, geographic location, and the interaction of evaluator and lactation number had a significant effect on most of the type traits and the scorecard category (General Appearance, Mammary System, Dairy Character and Body Capacity) scores examined. The effects of these variables were statistically removed and the residuals of the type traits were used in the final regression analysis. Using stepwise regression analysis, several non-significant traits were omitted from the final model. The analysis used days open and times bred as dependent variables. Lactation number, mature equivalent milk, foot angle, rump width and their respective quadratics were independent variables, as were season calved and geographic location. The regression analysis (R²) indicated that 5.3% of the variability in days open and 4.7% of the variability in times bred in registered cows was accounted for by the type traits, foot angle and rump width, respectively, when the effects of season calved, geographic location, lactation number and mature equivalent milk were included in the model. For the grade cows the regression analysis (R²) indicated that 3.5% of the variability in days open was accounted for by foot angle. None of the type traits examined had a significant effect on times bred. This study detected no significant influence of rump angle or rear leg position, as described by the HFA linear classification program, on reproductive performance. However, our analysis indicated that fertility decreased as rear foot angles became more steep in grade and registered cows and as rump width increased in registered cows. / Graduation date: 1991