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Thesis (Ph.D.)--York University, 2007. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 166-175). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39036

Includes bibliographical references (p. 104-119).

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves.

Thesis (M.S. in genetics and cell biology)--Washington State University, December 2008. / Title from PDF title page (viewed on Dec. 31, 2008). "School of Molecular Biosciences." Includes bibliographical references.

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1909. / Cover title. "Reprinted from Volume XVII, Part I of the Transactions of the Wisconsin Academy of Sciences, Arts, and Letters." Includes bibliographical references (p. 49-56).

Proefschrift--Utrecht. / Summaries in Dutch and English. "Stellingen" laid in. "Geraadpleegde literatuur":p. [56]-62.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1915. / Typescript. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 38-39.

Thesis (Ph.D.)--McMaster University, 2005. / Advisor: R. S. Singh. Includes bibliographical references. Also available online.

Made available in DSpace on 2014-06-11T19:35:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-15Bitstream added on 2014-06-13T19:24:35Z : No. of bitstreams: 1 castro_elc_dr_jabo.pdf: 458441 bytes, checksum: ea8d6d3919ec4a9e692914323b80803d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Três grupos de 8 touros, sendo cada grupo formado por 4 animais da raça Simental (Bos taurus taurus) e 4 da raça Nelore (Bos taurus indicus), perfazendo um total de 24 touros com idade aproximada de 30 meses foram submetidos a dietas isoenergéticas com diferentes níveis de proteína degradável no rúmen e água ad libitum. As rações foram constituídas basicamente de feno de Tifton 85, farelo de soja, milho e uréia (Nitrogênio Não Protéico) e formuladas individualmente para cada touro de acordo com a análise bromatológica dos ingredientes, peso e ingestão dos animais. Na dieta do grupo controle (C) foram seguidas as normas do NRC (1996) para nutrição de touros em reprodução. Na dieta do grupo gradual (G) foram acrescidas 30% e, após quatro semanas, 75% de proteína degradável em relação à dieta controle, através do aumento na quantidade fornecida de uréia (NNP). Na dieta do grupo Choque o nível de proteína degradável foi 110% superior à ração do grupo controle durante todo o período experimental. Os touros permaneceram em baias individuais e após o período de adaptação de 21 dias foram submetidos semanalmente a colheitas de sêmen. O sêmen dos animais foram obtidos por eletroejaculação e avaliados quanto aos exames físicos do sêmen (turbilhonamento, motilidade, vigor e concentração) e morfologia espermática durante o período experimental de 15 semanas. Foram realizadas colheitas semanais de sangue 2 horas após a alimentação dos animais com a finalidade de mensurar os níveis plasmáticos de amônia e uréia durante seu pico de produção. Os ejaculados dos touros dos grupos tratados (Cq e G) apresentaram menor turbilhonamento, motilidade, vigor e concentração em relação ao grupo controle (C) a partir da décima terceira semana de experimento (P<0,01). / Three experimental groups, each containing eight bulls, were given isoenergetic diets with different levels of ruminal-degradable protein and ad libitum water. Each group was constituted by four Fleckvieh (Bos taurus taurus) and four Nellore (Bos taurus indicus) bulls, in a total of 24 animals with mean age of 30 months. Diets were composed basically of Tifton 85 hay, soy bran, corn and urea (non-proteic nitrogen; NPN) and formulated for each animal individually, according to ingredients' bromatologic analysis, animal's weight and uptake capacity. For the Control-group (C-group) diet, NRC (1996) nutrition recommendations for bulls on reproduction were followed. In the Gradual-group (G-group) diet, 30% more ruminal-degradable protein (compared to the C-group) was added, and after four weeks, the level increased to 75% through the addition of urea (NPN). For the Choque-group (Cq-group), degradable protein level was 110% higher than in Cgroup during all experimental period. Bulls were maintained in individual boxes and after an adaptation period of 21 days, semen samples were collected. Semen was obtained through electroejaculation and analysed for physical (whirl movement, motility, vigour and concentration) and morphological characteristics during the period of 15 weeks. Blood sampling was performed weekly two hours after feeding in order to measure ammonia and ureal levels during its peak production. Treatment groups (Cq-group and G-group) presented lower whirl movement, motility, vigor and concentration than the C-group after the 13th week (P<0,01). Spermatic morphology showed increased levels of greater spermatic defects for taurines (P<0,05) during all experimental period, but no significant differences were observed among treatments for these characteristics. Significant differences in plasmatic urea (P<0,01) occurred.