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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

Perfil Hematológico e Bioquímico Sérico de Ovinos Infectados com Nematóides e Medicados com Ivermectina e Closantel / Hematologiy And Serum Biochemical Panel Sheep Infected with Nematodes and Dosed with Ivermectin and Closantel

Costa, Kizzy Millenn de Freitas Mendonça 08 September 2011 (has links)
Made available in DSpace on 2016-08-15T20:31:01Z (GMT). No. of bitstreams: 1 kizzyMFMC_DISSERT.pdf: 774522 bytes, checksum: da3661ec2a393e4af5e31278032e04d2 (MD5) Previous issue date: 2011-09-08 / Despite its known resistance, the sheep are subject to endoparasitoses, which are the main limiting factor for its production worldwide, especially in tropical regions. This study aims to evaluate the changes in parasitic load, serum biochemical and hematological panel, and Famacha scores of mixed-bred sheep naturally infected with nematodes and treated with ivermectin and closantel. The study was conducted at July 2010, in a farm in the municipality of Mossoró, Rio Grande do Norte state, Brazil. We selected 41 animals were divided into three groups: group I- control (without treatment), group II- treated with ivermectin (0.2 mg/kg), and Group III- treated with closantel (5 mg/kg). Stool samples were collected on days 0, 7, 14 and 21 after treatment for quantitative analysis (EPG) and qualitative analysis (stool culture), we used samples from days 0, 14 and 21. The first blood sample was given on day 0, the second and third 24 and 72 hours after the first, respectively the fourth and fifth 7 and 14 days after the first of which analyzed the blood count, serum total protein, albumin and globulins, and albumin/globulins ratio. Famacha scores were determined the degree of each animal at all times of sampling. Closantel administration was effective for the reduction of parasite counts, especially Haemonchus contortus, in evaluated sheep. On the other hand, there was parasite resistance to ivermectin. Famacha data showed negative correlation with packed cell volume, leukocytes, hemoglobin, albumin, total protein, globulin and albumin/globulin ratio. The packed cell volume showed a strong and positive correlation with hemoglobin, albumin and total protein. Treatment with ivermectin and closantel were not responsible for considerable changes in hematological and biochemical parameters evaluated. / Apesar de sua conhecida resistência, os ovinos estão sujeitos as endoparasitoses, sendo este o principal fator limitante para a sua produção em todo o mundo, especialmente em regiões tropicais. Este trabalho objetiva avaliar a carga parasitária, o perfil hematológico e bioquímico sérico, e o grau Famacha de ovinos sem padrão racial definido infectados e tratados com ivermectina e closantel. O trabalho foi realizado no mês de julho de 2010, numa propriedade rural no município de Mossoró-RN. Foram selecionados 41 animais, os quais foram divididos em três grupos: grupo I- controle (sem tratamento), grupo II- tratado com ivermectina (0,2 mg/kg) e Grupo III- tratado com closantel (5 mg/kg). As amostras de fezes foram coletadas nos dias 0, 7, 14 e 21, pós-tratamento para análise quantitativa (OPG) e para análise qualitativa (coprocultura), foram utilizadas amostras nos dias 0, 14 e 21. A primeira coleta de sangue se deu no dia 0, a segunda e a terceira 24 e 72 horas após a primeira, respectivamente, a quarta e a quinta 7 e 14 dias após a primeira, dos quais foram analisados o hemograma, os níveis séricos de proteínas totais, albumina e globulinas, e a relação albumina/globulinas. Foi determinado o grau de anemia pelo método Famacha de cada animal em todos os momentos de coleta de amostras. O tratamento com closantel foi eficaz na redução da carga parasitária, principalmente Haemonchus contortus, nos ovinos avaliados. Por outro lado, houve resistência dos parasitas à ivermectina. Os dados de Famacha apresentaram correlação negativa com volume globular, leucócitos, hemoglobina, albumina, proteínas totais, globulinas e relação albumina/globulinas. O volume globular apresentou uma correlação forte e positiva com hemoglobina, albumina e proteínas totais. Os tratamentos com closantel e ivermectina não foram responsáveis por alterações consideráveis nos parâmetros hematológicos e bioquímicos avaliados.
2

Speciation - What Can be Learned from a Flycatcher Hybrid Zone?

Wiley, Chris January 2006 (has links)
Studies of hybrid zones offer important insights into the process of speciation. Much of the knowledge to be gained is dependent on an accurate estimation of the strength of pre- and post-zygotic isolation between hybridizing taxa. My results demonstrate that hybridization can variously affect different components of fitness. In Ficedula flycatchers, late-breeding females may directly benefit from pairing with a heterospecific male by gaining access to superior territories. The hybrid offspring possess an immune system that is as equally well functioning as in the parental species (the collared, F. albicollis, and pied flycatcher, F. hypoleuca). However, I found that a severe reduction in fertility persists for at least three generations after the actual hybridization event. Combining all information about the reproductive success of hybridizing individuals and their descendents revealed that postzygotic isolation between flycatchers is very strong; hybridizing individuals leave almost no descendents. This thesis presents one of few comprehensive summaries of the selection for/against assortative mating in a natural hybrid zone. These findings suggest a central role for intrinsic postzygotic isolation as a reproductive barrier separating newly evolved bird species, and contrast previous suggestions that postmating isolation is the slowest of the reproductive barriers to evolve in birds. Despite this strong selection against hybridization, pre-mating isolation is incomplete. Hybridization often results from females lacking conspecific partners, but appears to be also caused by errors in species recognition. Much of this error probably reflects the short period of time that pied flycatchers on Gotland and Öland have been in sympatry. Compared to collared flycatchers, pied flycatchers are poorer able to discriminate between conspecific and heterospecific song, and male pied flycatchers more often falsely signal their own identity through heterospecific song copying. However, despite colonising the study site from other sympatric populations and having very little gene flow from allopatry, collared flycatchers also possess traits (e.g. delayed plumage maturation) that increase their hybridization risk. Once pre-mating isolation is strong, the rarity of hybridization probably inhibits further selection against traits promoting interspecific mating, especially when such traits may be beneficial in other contexts. This thesis highlights complex interactions between factors affecting hybridization rate that would not be detected if such a study were not field-based. Furthermore, it showcases likely examples in nature of a number of theoretical objections to the evolution of pre-mating barriers between populations living in sympatry.
3

Speciation - What Can be Learned from a Flycatcher Hybrid Zone?

Wiley, Chris January 2006 (has links)
<p>Studies of hybrid zones offer important insights into the process of speciation. Much of the knowledge to be gained is dependent on an accurate estimation of the strength of pre- and post-zygotic isolation between hybridizing taxa. My results demonstrate that hybridization can variously affect different components of fitness. In Ficedula flycatchers, late-breeding females may directly benefit from pairing with a heterospecific male by gaining access to superior territories. The hybrid offspring possess an immune system that is as equally well functioning as in the parental species (the collared, F. albicollis, and pied flycatcher, F. hypoleuca). However, I found that a severe reduction in fertility persists for at least three generations after the actual hybridization event. Combining all information about the reproductive success of hybridizing individuals and their descendents revealed that postzygotic isolation between flycatchers is very strong; hybridizing individuals leave almost no descendents. This thesis presents one of few comprehensive summaries of the selection for/against assortative mating in a natural hybrid zone. These findings suggest a central role for intrinsic postzygotic isolation as a reproductive barrier separating newly evolved bird species, and contrast previous suggestions that postmating isolation is the slowest of the reproductive barriers to evolve in birds.</p><p>Despite this strong selection against hybridization, pre-mating isolation is incomplete. Hybridization often results from females lacking conspecific partners, but appears to be also caused by errors in species recognition. Much of this error probably reflects the short period of time that pied flycatchers on Gotland and Öland have been in sympatry. Compared to collared flycatchers, pied flycatchers are poorer able to discriminate between conspecific and heterospecific song, and male pied flycatchers more often falsely signal their own identity through heterospecific song copying. However, despite colonising the study site from other sympatric populations and having very little gene flow from allopatry, collared flycatchers also possess traits (e.g. delayed plumage maturation) that increase their hybridization risk. Once pre-mating isolation is strong, the rarity of hybridization probably inhibits further selection against traits promoting interspecific mating, especially when such traits may be beneficial in other contexts. This thesis highlights complex interactions between factors affecting hybridization rate that would not be detected if such a study were not field-based. Furthermore, it showcases likely examples in nature of a number of theoretical objections to the evolution of pre-mating barriers between populations living in sympatry.</p>

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