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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Development of an in vivo model of inflammation in cattle

Haddock, Frances Miriam January 1993 (has links)
No description available.
2

Ruminant parasitic gastroenteritis : some observations on epidemiology and control

Bairden, Kenneth January 1991 (has links)
No description available.
3

Bovine leukosis virus and cell kinetics

Takashima, Ikuo. January 1900 (has links)
Thesis--University of Wisconsin--Madison. / Typescript. Vita. Description based on print version record. Includes bibliographical references.
4

Bovine leukemia virus transmission studies

Baumgartener, Lois E. January 1981 (has links)
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.
5

Influência da ingestão de matéria seca e da condição corporal na produção in vitro de embriões bovinos

Bastos, Michele Ricieri [UNESP] 13 June 2008 (has links) (PDF)
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.
6

The development of a new strategy for the sustainable control of bovine trypanosomosis in Southern Africa

Van den Bossche, Peter 22 September 2010 (has links)
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
7

Decreasing perinatal bovine leukosis virus infection in calves

Nagy, Dusty W., January 2006 (has links)
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.
8

Effective detection of epidemiologically significant persistent infections of bovine viral diarrhea virus

Abrams, Misty Sue, Givens, Maurice Daniel, January 2006 (has links) (PDF)
Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.
9

Postmortem regulation of glycolysis by 6-phosphofructokinase in bovine muscle

Rhoades, Ryan D. 15 November 2004 (has links)
This study was conducted to assess the regulation of glycolysis by 6phosphofructokinase (PFK) during the postmortem metabolism of beef muscle. In the first experiment, M. sternocephalicus pars mandibularis samples were excised from six randomly-selected steers. Two samples were obtained from each steer immediately postmortem; one sample was quickly immersed in liquid nitrogen and the other was stored at 4oC for 4 d. Glycogen concentrations decreased 45% from d 0 to d 4, and 39.6 ?mol/g of glycogen was still present in the tissue at d 4. Concentrations of free glucose increased (P < 0.001) from 0.84 ?mol/g at d 0 to 6.54 ?mol/g at d 4. Fructose-6-phosphate (F6P) and glucose-6-phosphate (G6P) increased (P < 0.001) from d 0 to d 4 (2.8-fold and 4.7-fold, respectively). Lactate began accumulating immediately (3.33 ?mol/g) and was elevated to 45.9 ?mol/g by d 4. Glycolytic potential was 34.4 ?mol/g higher (P < 0.05) when measured at d 0 than at d 4. The greatest activity of PFK was measured in fresh muscle extracts, between pH 7.4-7.8; by reducing the pH to 7.0, PFK activity was depressed by nearly 50% at 1 mM F6P. In a second experiment, M. longissimus lumborum samples were excised at the 13th thoracic rib location from six randomly-selected steers. Samples were obtained at intervals ranging from 40 min to 24 h postmortem. Glycogen concentrations decreased 45% between 40 and 100 min, and tended (P &#8804; 0.10) to decrease between 100 min and 24 h (from 47 to 32 ?mol/g). Concentrations of free glucose increased (P &#8804; 0.009) from 1.0 ?mol/g at 40 min to 5.0 ?mol/g at 24 h. Concentrations of F6P and G6P increased dramatically after 100 min (muscle pH &#8804; 6.5), whereas glycogen depletion appeared to halt by 100 min. Lactate began accumulating almost immediately and tripled in concentration by 24 h. The elevation of G6P and F6P, coupled with the pH sensitivity of PFK, indicate that the postmortem decline in pH ultimately inactivates PFK prior to glycogen depletion.
10

Expression of the bovine DNA (cytosine 5) methyltransferase family during preimplantation development and aberrations induced by somatic cell nuclear transfer

Golding, Michael Cameron 17 February 2005 (has links)
Bovine preimplantation embryos derived from nuclear transfer experiments exhibit a global state of genomic hypermethylation that likely account for the large number of developmental abnormalities observed to date. The central hypotheses of this work is that the genomic hypermethylation and improper epigenetic reprogramming reported in studies of bovine nuclear transfer, are in large part due to abnormal expression and regulation of the DNA methyltransferase proteins. Bovine Dnmt mRNAs display strong sequence homology to those of human and mouse and similar to other species, exist as multiple isoforms. Two of these splice variants, which have been termed Dnmt2&#947; and Dnmt3a4 represent previously unreported sequence combinations. Investigation of bovine DNA methyltransferase expression in the bovine oocyte and early preimplantation development has revealed an intricate system divergent from observations previously reported in the mouse. Specifically, the somatic version of Dnmt1 along with Dnmt2, 3a and 3b are all expressed during these initial stages of bovine development. Further, real time analyses of the Dnmt transcripts in cloned and in vitro produced embryos reveal significant differences in the mRNA expression levels of Dnmt1 and 2 but not Dnmt3a and 3b suggesting that the de novo methyltransferases may be functioning normally while Dnmt1 and Dnmt2 are aberrantly methylating the genome during a critical time when methylation levels should be receding. Real time PCR analysis of the Dnmt transcripts in fetal and adult tissues has revealed a developmental and tissue specific expression pattern suggesting that proper expression and function of these enzymes is a key element in the process of differentiation. These results are further supported by studies of Dnmt expression in aging bovine fibroblast cultures, which suggest that the Dnmts may play some as yet unidentified role in cellular senescence. Recently, it has been postulated that the cause of abnormal methylation observed in cloned embryos may be due in part to misexpression of the Dnmt1o isoform during preimplantation development. Work presented here raises new and significant hypotheses that must be considered both regarding the cadre of DNA methyltranferases that direct epigenetic programming during normal development and regarding the implication of abnormal DNMT expression in cloned embryos. Bovine preimplantation embryos derived from nuclear transfer experiments exhibit a global state of genomic hypermethylation that likely account for the large number of developmental abnormalities observed to date. The central hypotheses of this work is that the genomic hypermethylation and improper epigenetic reprogramming reported in studies of bovine nuclear transfer, are in large part due to abnormal expression and regulation of the DNA methyltransferase proteins. Bovine Dnmt mRNAs display strong sequence homology to those of human and mouse and similar to other species, exist as multiple isoforms. Two of these splice variants, which have been termed Dnmt2&#947; and Dnmt3a4 represent previously unreported sequence combinations. Investigation of bovine DNA methyltransferase expression in the bovine oocyte and early preimplantation development has revealed an intricate system divergent from observations previously reported in the mouse. Specifically, the somatic version of Dnmt1 along with Dnmt2, 3a and 3b are all expressed during these initial stages of bovine development. Further, real time analyses of the Dnmt transcripts in cloned and in vitro produced embryos reveal significant differences in the mRNA expression levels of Dnmt1 and 2 but not Dnmt3a and 3b suggesting that the de novo methyltransferases may be functioning normally while Dnmt1 and Dnmt2 are aberrantly methylating the genome during a critical time when methylation levels should be receding. Real time PCR analysis of the Dnmt transcripts in fetal and adult tissues has revealed a developmental and tissue specific expression pattern suggesting that proper expression and function of these enzymes is a key element in the process of differentiation. These results are further supported by studies of Dnmt expression in aging bovine fibroblast cultures, which suggest that the Dnmts may play some as yet unidentified role in cellular senescence. Recently, it has been postulated that the cause of abnormal methylation observed in cloned embryos may be due in part to misexpression of the Dnmt1o isoform during preimplantation development. Work presented here raises new and significant hypotheses that must be considered both regarding the cadre of DNA methyltranferases that direct epigenetic programming during normal development and regarding the implication of abnormal DNMT expression in cloned embryos.

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