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Thesis--University of Wisconsin--Madison. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1981. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:29:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-06-13Bitstream added on 2014-06-13T19:38:30Z : No. of bitstreams: 1 bastos_mr_me_botfmvz.pdf: 790909 bytes, checksum: 06b5f7cf1b70d4316f61ff63d1907d62 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivou-se avaliar o efeito da condição corporal e/ou da alta ingestão de matéria seca (AIMS) na produção in vivo de embriões de fêmeas bovinas superovuladas. Em um primeiro experimento, 14 vacas Simental x Nelore não-lactantes com elevado escore de condição corporal (ECC) foram divididas em grupos de Manutenção=M ou alta ingestão de matéria seca=AIMS. As vacas do grupo AIMS receberam dieta com 180% da manutenção, entre 7 dias antes do início da superovulação (SOV) e o final das aplicações de FSH. O grupo M recebeu dieta de manutenção. O número de folículos recrutados e ovulados não diferiu entre os grupos (P>0,10). Entretanto, os números de estruturas totais e embriões viáveis colhidos foram maiores no grupo M (P<0,05). Em um segundo experimento avaliou-se a influência do ECC associado ou não da AIMS na produção embrionária em 36 novilhas Nelore. AIMS ocorreu por 14 dias antes do início da SOV. Após colheita, os embriões viáveis foram congelados para posterior cultivo até eclosão. Não houve diferença entre os grupos na população folicular ao início da SOV, na resposta superestimulatória ou superovulatória, nem no número ou qualidade dos embriões colhidos. As novilhas com <ECC apresentaram maiores concentrações séricas de IGF-I, entretanto as com >ECC tiveram insulina mais alta. Os embriões dos animais com >ECC apresentaram diâmetro, taxas de eclosão e expressão relativa de mRNA do gene BAX superiores após cultivo do que os coletados no grupo com <ECC. Os resultados conflitantes entre os experimentos e com dados da literatura sugerem haver diferentes respostas à alimentação dependendo da raça ou estado nutricional na produção embrionária. / The aim of this study was to investigate the effect of body condition and/or high dry matter intake (flushing) on in vivo embryo production in superovulated female cattle. A first experiment used 14 non-lactating Nelore x Simmental cows with a high body condition score (BCS) divided into Maintenance=M or Flushing=F groups. Seven days prior to onset of superovulation (SOV) until the last day of treatment with FSH, group F cows were fed a diet to achieve 180% of maintenance. Group M cows were fed a maintenance diet. The number of recruited or ovulated follicles did not differ between groups (P>0.10). However, the total number of embryos/ova and the number of viable embryos recovered were greater in the M group (P<0.05). A second study investigated whether differences in BCS, associated or not with nutritional flushing, influence the embryo production in 36 Nelore heifers. Nutritional flushing was conducted during 14 days prior to the onset of SOV. After recovery, viable embryos were frozen to be subsequently cultured until hatching. There was no difference among groups for follicle population at onset of SOV, superstimulatory or superovulatory responses, nor number or quality of recovered embryos. Heifers with <BCS had grater blood concentrations of IGF-I, whereas heifers with >BCS had grater insulin. Embryos collected from >BCS heifers had greater diameter, hatching rates and relative expression of the BAX gene mRNA than the ones recovered from <BCS heifers. The conflicting results between the experiments and also in relation to data from the literature suggest that there are different responses to diets depending on animal breed or nutritional status on embryo production.

Previously, strategy formulation for large-scale eradication of tsetse in southern Africawas dominated by straightforward technical considerations. The current shift to localised control of tsetse-transmitted bovine trypanosomosis has changed the emphasis from the vector to the disease. Nagana remains the main reason for intervening but control methods will differ according to the local situation and interventions will be restricted to those areas where the disease is present. As a result, the technical criteria to be considered will differ substantially from those considered in the planning for large-scale eradication. First, a clear picture of the extent and magnitude of the bovine trypanosomosis problem is required. Second, the selection ofthe most efficient intervention methods will vary according to the local epidemiological situation. Hence, the different epidemiological situations need to be identified and the effectiveness of available control methods needs to be evaluated in each of the situations. Finally, the long-term sustainability of an intervention will depend, to a large extent, upon the socio-economic impact of the disease and perceived benefits accruing from its control. Tsetse-transmitted bovine trypanosomosis occurs in large areas of Malawi, Zambia,Zimbabwe and Namibia. The epidemiology of the disease differs substantially between areas. On the plateau of eastern Zambia, for example, cattle are kept in a tsetse infested area. Because of the encroachment of people and cattle into the tsetse infested area and the concomitant reduction in the number of game animals, tsetse have become highly dependent on cattle as their source of food. As a result, the distribution and density of tsetse is determined largely by the distribution and changes in the distribution or grazing pattern of cattle. Trypanosoma congolense is the main.trypanosome species in tsetse and cattle. The prevalence of congolense-type trypanosomal infections in tsetse undergoes little variations between months and is affected mainly by the average age of the tsetse population. The incidence of bovine trypanosomosis is significantly correlated with the density of the tsetse population.Bovine trypanosomosis is also prevalent in areas where cattle are kept adjacent to a tsetse-infested zone or where tsetse occasionally invade a tsetse-free area. In Malawi,for example, the main foci of bovine trypanosomosis are located adjacent to tsetse infested national parks, game reserves or forest reserves. Bovine trypanosomosis also occurs far outside the known tsetse foci because of the seasonal movement of tsetse,along rivers or because of, often small, undetected tsetse foci. Such foci have been detected in Malawi and in Zimbabwe. In most of the areas, bovine trypanosomosis is caused by T congolense. However, the prevalence of T vivax infections is high in areas where tsetse take a large proportion of feeds on game animals. Please read the full abstract in the section 00 front of this document. / Thesis (PhD)--University of Pretoria, 2000. / Veterinary Tropical Diseases / unrestricted

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2006. / Title from title screen of research.pdf file (viewed on December 22, 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. Vita. "May 2006" Includes bibliographical references.

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