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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.
11

Caracterização patológica e molecular do vírus da Bouba Aviária como contribuição para elaboração de padrão de condenação para carcaças de perus

Ferreira, Bruna Custódio 23 January 2015 (has links)
Fundação de Amparo a Pesquisa do Estado de Minas Gerais / This study described the first outbreak of avian fowlpox in Brazil in previously vaccinated turkeys and also established, in an attempt to help the Federal Inspection Service, a standard of condemnation for carcasses with lesions characteristic of fowlpox. The turkeys had crusted macroscopic lesions on their skin, suggestive of avian fowlpox in the head and neck and no additional clinical signs were observed. The mortality rates in the flock did not change. In the slaughterhouse, 30 carcasses were removed from the slaughter line to collect damaged skin fragments for its characterization and research of the virus. The samples were fixed in formalin, embedded in paraffin, cut into sections of 6 microns and stained with hematoxylin-eosin for viewing in microscope. The agent identification was performed by conventional PCR with subsequent sequencing of the gene fpv167. On histopathology were observed: hyperkeratosis, acanthosis and hydropic degeneration; the presence of eosinophilic intracytoplasmic inclusion corpuscles (Bollinger) was observed in keratinocytes in 46.6% of samples. The PCR reaction was positive in 83.3% of samples. Using both diagnostic techniques was determined that 93.3% of the samples were positive for fowlpox. In the phylogenetic study, the samples show 100% of identity to each other suggesting that the outbreak occurred by a single virus strain. The sequenced gene fragment did not allow differentiation between strains of virus that infect turkeys, chickens or vaccinal strain. The fowlpox virus is avian species specific, and there are no reports of its occurrence in mammals. According to the macroscopic and microscopic characteristics of the skin lesions is not justified total condemnation of turkey\'s carcasses affected by avian fowlpox, except in cases of cachexia, disgusting aspect and other specifications at Federal Inspection Service regulations. Studies including the sequencing of other genes are needed to better viral characterization and can assist in identifying origin of the etiologic agent responsible for the outbreak and its possible sources. / Esse estudo descreveu o primeiro surto de bouba aviária no Brasil em perus de corte previamente vacinados e também estabeleceu, na tentativa de auxiliar o Serviço de Inspeção Federal, um padrão de condenação para carcaças apresentando lesões características de bouba aviária. As aves apresentaram lesões cutâneas crostosas macroscópicas sugestivas de bouba aviária na região da cabeça e do pescoço e nenhum sinal clínico adicional foram observados. Os índices de mortalidade no lote não foram alterados. No frigorífico, 30 carcaças foram retiradas da linha de abate para coleta de fragmentos de pele lesionada para sua caracterização e pesquisa do vírus. As amostras foram fixadas em formol, embebidas em parafina, cortadas em secções de 6 μm e coradas pela técnica de hematoxilina-eosina para visualização em microscópio de luz clara. A identificação do agente foi realizada por meio da técnica de PCR convencional com posterior sequenciamento do gene fpv167. No exame histopatológico foram observados: hiperqueratose, acantose e degeneração hidrópica; a presença de corpúsculos de inclusão intracitoplasmáticos eosinofílicos (Bollinger) nos queratinócitos foi observada em 46,6% das amostras. A reação de PCR foi positiva para 83,3% das amostras. Com o uso das duas técnicas de diagnóstico foi possível determinar que 93,3% das amostras foram positivas para bouba aviária. No estudo filogenético realizado, as amostras apresentam 100% de identidade entre si sugerindo que o surto ocorreu por uma única estirpe de vírus. O fragmento do gene sequenciado não permitiu a diferenciação entre estirpes de vírus que infectam perus, vacinal ou de galinhas. O vírus da bouba aviária é espécie específica, e não existem relatos sobre sua ocorrência em mamíferos. De acordo com as características macroscópicas e microscópicas das lesões cutâneas, não se justifica a condenação total das carcaças das aves acometidas pelo vírus da bouba aviária, exceto nos casos de caquexia, aspecto repugnante e outros especificados nos regulamentos do SIF. Estudos incluindo o sequenciamento de outros genes são necessários para melhor caracterização viral e podem auxiliar na identificação da origem do agente etiológico responsável pelo surto e suas possíveis fontes. / Mestre em Ciências Veterinárias
12

Non-Linear Density Dependence in a Stochastic Wild Turkey Harvest Model

McGhee, Jay D. 23 February 2006 (has links)
Current eastern wild turkey (<I>Meleagris gallopavo silvestris</I>) harvest models assume density-independent population dynamics despite indications that populations are subject to a form of density dependence. I suggest that both density-dependent and independent factors operate simultaneously on wild turkey populations, where the relative strength of each is governed by population density. I attempt to estimate the form of the density dependence relationship in wild turkey population growth using the theta-Ricker model. Density-independent relationships are explored between production and rainfall and temperature correlates for possible inclusion in the harvest model. Density-dependent and independent effects are then combined in the model to compare multiple harvest strategies. To estimate a functional relationship between population growth and density, I fit the theta-Ricker model to harvest index time-series from 11 state wildlife agencies. To model density-independent effects on population growth, I explored the ability of rainfall, temperature, and mast during the nesting and brooding season to predict observed production indices for 7 states. I then built a harvest model incorporating estimates to determine their influence on the mean and variability of the fall and spring harvest. Estimated density-dependent growth rates produced a left-skewed yield curve maximized at ~40% of carrying capacity, with large residuals. Density-independent models of production varied widely and were characterized by high model uncertainty. Results indicate a non-linear density dependence effect strongest at low population densities. High residuals from the model fit indicate that extrinsic factors will overshadow density-dependent factors at most population densities. However, environmental models were weak, requiring more data with higher precision. This indicates that density-independence can be correctly and more easily modeled as random error. The constructed model uses both density dependence and density-independent stochastic error as a tool to explore harvest strategies for biologists. The inclusion of weak density dependence changes expected harvest rates little from density-independent models. However, it does lower the probability of overharvest at low densities. Alternatives to proportional harvesting are explored to reduce the uncertainty in annual harvests. / Ph. D.
13

Use of Satellite Imagery and GIS to Model Brood-Rearing Habitat for Rio Grande Wild Turkey Populations Occurring in the Western Cross Timbers Region of Texas

Miller, Christopher J. 08 1900 (has links)
Remote sensing and GIS have become standard tools for evaluating spatial components of wildlife habitats. These techniques were implemented to evaluate Rio Grande wild turkey (Meleagris gallopavo) poult-rearing habitat in the Western Cross Timbers region of Texas. Texas Parks and Wildlife (TPWD) random roving turkey counts for 1987-1989 and 1998-2000 were selected, indicating locations where hens with poults were observed. Satellite imagery from 1988 and 1999 was classified and then processed with Patch Analyst. To add robustness, stream, road and census population densities were also evaluated for each turkey location. Analysis of the 1988 canopy cover image, comparing observed locations with randomly-selected habitat cells (N = 20) indicated significant differences (p <.05) for patch edge variables. Mean patch edge was significantly greater for habitat locations where hens with poults were observed than for those selected at random. Spatial data for 1999 did not indicate a significant difference (p < .05) between sampling groups (observed vs. random, N = 30). Significant differences (p <.05) did occur for turkey locations observed in both 1988 and 1999 (N = 7). This demonstrates the adaptability of wild turkey hens, as habitats change over time, hens continued to visit the same locations even though the habitat had significantly changed for select spatial variables.
14

Reproductive ecology of Rio Grande wild turkey in the Edwards Plateau of Texas

Melton, Kyle Brady 15 May 2009 (has links)
The abundance of Rio Grande wild turkeys (Meleagris gallopavo intermedia) in the southeastern Edwards Plateau of Texas has declined since the late 1970s. Because knowledge of reproductive rates is important to understanding the dynamics of a population, radio-tagged hens were monitored during the 2005–2007 reproductive seasons to evaluate and compare reproductive parameters from areas with both declining and stable population trends. During January–March of 2005–2007, turkey hens were captured and radiotagged on 4 study areas; 2 within a region of stable turkey populations, and 2 within a region of declining populations. Monitoring occurred from January–July each season to determine nest- site locations. Nesting attempts, nest fate, clutch size, initiation date, and nest age were recorded. Nests were monitored ≥3 times weekly in order to estimate production parameters and daily nest survival. Poults were captured by hand and fitted with a 1.2 glue-on transmitter and monitored daily to estimate daily survival. Estimates show production was greater in stable regions than declining regions of the Edwards Plateau. Eighty-four percent of hens attempted to nest in the stable region and 67% attempted in the declining region. Eighteen of 102 nests were successful (≥1 egg hatched), in the stable region and 7 of 60 nests were successful in the declining region. Nest-survival analysis showed an influence of temporal variation within years, yet no differences in nest survival were detected between stable and declining regions. Poult survival also showed no difference between regions. The 2 overall objectives of this study were to determine if nesting parameters and nest survival were limiting factors in Rio Grande wild turkey abundance in the Edwards Plateau. Regional differences in production suggest the cause of the decline in the southeastern portion of the Edwards Plateau could be associated with lower reproductive output and consequently, success. Regional differences in nest survival were not detected, thus not likely to cause differences in turkey abundance between regions.

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