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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

The influence of dual CYP17 expression on adrenal steroidogenesis in the South African Angora Goat

Storbeck, Karl-Heinz 12 1900 (has links)
Thesis (PhD (Biochemistry))--Stellenbosch University, 2008. / This study describes: • the cloning and sequencing of cytochrome P450 17 -hydroxylase/17,20 lyase (CYP17), 3 -hydroxysteroid dehydrogenase (3 HSD) and cytochrome b5 from the South African Angora goat; • the identification of two CYP17 genes encoding two unique CYP17 isoforms in the Angora goat; • the development of a UPLC-APCI-LC method for the separation and quantification of seven adrenal steroids; • the characterisation of the enzymatic activity of the two Angora CYP17 isoforms expressed in non-steroidogenic COS-1 cells. The Km and Vvalues for the metabolism of pregnenolone and progesterone were determined; • the development of a rapid and accurate real-time PCR genotyping test for CYP17 in Angora goats. Three unique genotypes were identified; • the determination of blood cortisol levels upon the stimulation of the HPAaxis by intravenous insulin injection in the three Angora goat genotypes.
12

Attenuated heartwater vaccine (Ehrlichia ruminantium Welgevonden) : immunization of Angora goats using the intra-muscular route of administration

Haw, Anna January 2013 (has links)
Ehrlichia ruminantium, the causative organism of heartwater infections, places severe economic constraint on the livestock industry wherever Amblyomma tick vectors are present. Angora goats are particularly susceptible to this disease and the current live blood vaccine cannot safely be used to protect these animals. An attenuated E. ruminantium (Welgevonden) experimental vaccine has previously shown promising results in Merino sheep and Boer goats. The vaccine was administered by intravenous route (i/v). The general objective of this study was to test the efficacy and safety of the attenuated heartwater vaccine E. ruminantium (Welgevonden) in Angora goats. The specific objectives were, firstly to assess the intra-muscular route of administration of the attenuated vaccine as compared to the standard i/v route and, secondly, to study the haematological changes in Angora goats before, during and after vaccination under controlled conditions at the Onderstepoort Veterinary Institute tick-free stables. A total of 55 Angora goats were used in this trial. They were purchased from an area in South Africa which is known to be Amblyomma-free and heartwater-free. Furthermore, on arrival, the goats were screened for E. ruminantium infection by the immunofluorescent antibody (IFA) test to confirm their disease-free status. The Angora goats were divided into 3 groups: In Group 1, ten were vaccinated by the standard i/v route, in Group 2, 31 received the vaccine by i/m route and 10 served as untreated controls for Group 3. Five of the 10 i/v vaccinated group, 20/31 of the i/m vaccinated and 5 controls were challenged by feeding of known infected adult A hebreaum. The other remaining animals within the three groups were challenged using a known infected blood stabilate administered by the standard i/v route (dose 5xLD50). All animals were challenged 42 days after vaccination. The vaccine did not produce any inflammatory reactions at the site of injection. However, 3/31 (9.7%) of i/m and 7/10 (70%) of i/v vaccinated goats developed febrile reactions starting on Day 11 post-immunisation and were treated. All vaccinated goats were fully protected against either needle i/v or tick challenge, while the control non-vaccinated goats reacted severely to the challenge materials and required oxytetracycline treatment. Despite treatment, two of the unvaccinated goats died from the challenge material. 9 Haematological values (packed cell volume, differential blood cells count) were obtained on blood samples taken from the treatment and control groups at different times during the course of the trial. Wide within group variations as shown by the high standard deviation values were found. As no significant changes were found between vaccinated and control animals, it is likely that the attenuated vaccine does not cause significant clinical haematological changes. This study has demonstrated that the attenuated E. ruminantium (Welgevonden) vaccine is safe in 90.3% and efficacious (100% efficacy) for intramuscular administration in Angora goats. However, further laboratory and on-farms studies are needed in order to establish the lowest effective and safety dose, duration of immunity, and the vaccine’s safety in young and pregnant animals. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Veterinary Tropical Diseases / unrestricted
13

A molecular approach to genetic improvement of South African Angora goats

Visser, Carina 19 October 2011 (has links)
South Africa is considered the primary producer and most reliable source of high quality clip mohair in the world. The application of molecular technologies to improve mohair quality is relatively new to this industry. The aim of the study was to use a molecular approach to genetically improve South African Angora goats, with emphasis on mohair production. A reference population of Angora goats was firstly established consisting of twelve sire families with half-sib offspring (1067 individuals in total). The genetic variation of this population was evaluated using microsatellite markers and the average gene diversity was found to be above 60%. Ninety four microsatellite markers were then genotyped on the reference population, spanning 23 chromosomes (total length 1352cM) with an average marker interval of 23.0cM. This information was used to improve previously published goat linkage maps. Unmapped microsatellite markers were incorporated and previously published inter-chromosomal rearrangements between the goat and sheep genetic maps were confirmed or rejected. Nine new markers were mapped to the goat genome, and six chromosomes showed rearrangement when compared to the previous goat map. Four previously reported intra-chromosomal rearrangements were shown to be either population specific or mapping errors. Variance components and genetic parameters of mohair traits (FW, FD, CVFD, SDFD, CF, SF and SDA) were estimated; including the fibre diameter profile measured using OFDA technology that has not yet been included in genetic evaluations. Heritability estimates ranged between 0.14 (SDA) and 0.63 (CF). OFDA-measured traits should be considered for inclusion into the national breeding strategy. The reference population was lastly analysed to identify QTL associated with fleece traits. Eighteen putative QTL were identified for seven mohair traits on 13 chromosomes. Three putative QTL were detected for FW on CHI 2, 5 and 24 corresponding with KRT and KAP gene locations. Two QTL associated with mohair FD (on CHI 4 and 24) were detected. QTL contributions to variance ranged between 7.44% (CF) and 19.69% (SDA). The results of this study should form part of an integrated approach where both quantitative and molecular tools are applied for genetic improvement of South African Angora goats. / Thesis (PhD)--University of Pretoria, 2011. / Animal and Wildlife Sciences / PhD / Unrestricted
14

Adoption of non-traditional enterprises by Virginia farmers

Zhou, Xiaofeng 11 July 2009 (has links)
This study investigates the role of non-traditional enterprises in rural economies and attempts to understand farmers’ decision to adopt non-traditional enterprises. Three separate mail surveys were conducted to collect socio-economic data from biological and organic, Angora goat, and ginseng farm enterprises. Descriptive statistics, Pearson χ² tests, and multinomial logit models were used to accomplish the objectives of the study. The analysis focuses on biological and organic, and Angora goat enterprises. The results of the analysis show that the principal operators of these enterprises were significantly younger, better-educated, better-off, and more likely to be a female in comparison to all Virginia farmers. The majority of farm operators came from non-rural backgrounds and their principal occupation is not farming. Only a very small percentage cited economic factors as the most important reason for starting the non-traditional enterprises. The most common information source used for planning and developing these new enterprises is books, magazines, or newsletters. The majority of respondents in both the biological/organic and Angora goat surveys did not perform any feasibility analyses prior to beginning their non-traditional enterprises. The farmers rated production and marketing as their major problems. In general, the majority of biological and organic farms and Angora goat farms were not profitable in 1993, and the income from these enterprises contributed very little to household income. However, it was found that biological and organic enterprises have played an important role in the economic survival of farmers with financial obstacles. The majority of farmers in the samples saw a bright future for their products. / Master of Science
15

Suburbanization In Turkiye Within The Process Of Integration To Global Development And A New Life-style Settlement

Erisen, Oya 01 December 2003 (has links) (PDF)
This study aims to analyze the emergence and evaluation of a new type of suburbanization in T&uuml / rkiye, which are concomitant with the rise of new middle class having a high purchasing power. It examines different urbanization and suburbanization processes in various societies and demonstrates that the suburbanization of T&uuml / rkiye does not exactly fit in these models. Such a suburban expansion is taking place under the prevailing impact of political economy in the world and leads to a social segregation within metropolitan areas, which is argued to become permanent. Upper middle class have developed privatized, enclosed, and monitored exclusive spaces of residence, work, leisure, and consumption. The main focus of the study, therefore, is the gated communities, which is the last extension of suburbanization. In this thesis, the gated communities are mainly residential in character and offer a new concept of life-style, which is based upon the idea of total security and retreat from the illnesses of the urban core in terms of noise, dust, disorder, crowds and related issues. It is argued that, in the specific case of Angora Evleri-Kooperatif-18, gated communities can be viewed as a further theme of fragmentation of the city of Ankara. The new urban fragmentation indicates a dual process of increasing social and spatial polarization on the urban land. These dualities have been identified in society. One part of the society has experienced affluence, and success while the other has suffered degradation. The economic growth has been at the expense of sharp increases both at the top and bottom ends of the income distribution. Social inequality, in return, has manifested itself spatially.
16

Fiber growth of goats as influenced by the doe's genotype, plane of nutrition and physiological stage (gestation and lactation)

Ngwekhulu, Livhuwani 19 August 2005 (has links)
The full text of this thesis/dissertation is not available online. Please <a href="mailto:upetd@up.ac.za">contact us</a> if you need access. Read the abstract in the section 00front of this document. / Dissertation (M Inst Agrar (Animal Production))--University of Pretoria, 2006. / Animal and Wildlife Sciences / unrestricted
17

Genetic characterization of commercial goat populations in South Africa

Pieters, Anelle 29 July 2008 (has links)
A genetic study of four commercial goat breeds in South Africa was performed using microsatellite markers. The commercial breeds included the Boer goat, Savanna, Kalahari Red and the Angora goat. Indigenous goat populations from Delftzijl and Groblersdal were also included in this study. Seventeen microsatellite markers were tested to determine the genetic variation. Genetic variation within the breeds were relatively high with heterozygosity values ranging from 57% for the Boer goat, 68% for the Kalahari Red, 69% for the Savanna goats and 70% for the Angora goats. First values indicated that the Savanna and Boer goat are genetically the closest (0.114), while the Kalahari Red and Boer goat are the least related (0.237). Phenotypic measurements included height, length, depth, heart girth, pelvic length and width for a phenotypic description. Significant differences were observed in the phenotypic measurements among all the breeds. The genetic and phenotypic differences indicate that these goats can be distinguished as different breeds. Results of this study contribute genotypic information of the commercial goats in South Africa. Copyright / Dissertation (MSc)--University of Pretoria, 2007. / Animal and Wildlife Sciences / unrestricted
18

Determining thermal stress during the transport of mammals

Wimberger, Kirsten 01 November 2006 (has links)
Student Number: 0218322F Master of Science School of Physiology / The high morbidity and mortality of wild mammals and livestock during capture and transport is generally ascribed to thermal stress. Consequently, capture operators can benefit from improved methods that may reduce thermal stress. The aim of my study was to develop a practical method of measuring the body temperature of mammals during capture and transport operations. Firstly, I determined whether intermittent temperature recordings, which allow for minuteby- minute monitoring of an animal’s temperature, could accurately reflect continuous measures of an animal’s rectal temperature. Intermittent temperatures were measured via telemetry while continuous and off-line recordings were measured with data loggers. Secondly, I compared rectal and abdominal temperatures to determine if rectal temperature can provide a practical, noninvasive method of estimating core body temperature. Additionally, I measured body temperature and environmental conditions throughout transportation and compared pre- and post-transport levels of faecal cortisol, and blood cortisol, haematocrit and catecholamines. Measuring rectal temperatures seems to be the only feasible, non-invasive technique to obtain temperature during transport operations. However, rectal temperature records required about 30 minutes to stabilise after inserting a thermometric device. After rectal temperature stabilised, generally the difference between abdominal and rectal temperatures varied greatly for individual animals, while the average differences in temperatures between the body sites were not significant for all, except one, species. I have also shown that telemeters and data loggers can be used interchangeably to measure the body temperature of animals. The differences between temperatures measured by the devices were not significant, except for substantial differences shown in two animals. The addition of earphones and a large aerial inside the vehicle improved the telemetry results, by limiting the extraneous noise of the capture and transport environment. These conditions probably caused the anomalous readings in the two animals. General thermal responses to stress are that animals showed a peak in temperature due to capture and a decrease in temperature during transport. Therefore, capture-related stress and the likelihood of animals dying during capture could be minimised by ensuring that the animals are not chased longer than a set cut-off time. Further, globe temperature should be monitored to ensure that animals are not captured in high thermal conditions. In contradiction with the current guidelines regarding the appropriate time of day for capture, I recommend that animals should not be caught at the end of the day, as my results show that this is when their body temperatures are the highest. Body temperatures during transport and differences in faeces cortisol before and after transport seem to indicate that animals adapt to repeated stress events.
19

An ecological study of the ixodid tick rhipicephalus glabroscutatum (Du Toit, 1941)

Macivor, Keith Malcolm de Falloux January 1983 (has links)
An intensive study was conducted on the free-living larvae and parasitic life stages of R.glabroscutatum on Angora and Boer goats in the Uitenhage district. Free-living larvae exhibited periods of maximum relative abundance during months of generally lower rainfall, from the end of autumn to the beginning of spring. Relative larval abundance in open and gully sites was low while larvae were rarely found in bush sites. Relative abundance was higher at 20h00 than at 08h00 and 14h00. Repeated sampling in the same areas did not reduce larval numbers. Over 99% of parasitic ticks removed from Angora and Boer goats were located on the feet. The annual occurrence of a low and variable number of parasitic immatures was synchronous with the occurrence of free-living larvae. High, less variable numbers of adult ticks were removed from goat feet from September to December, the highest numbers being recorded during October and November. The occurrence of a single period of parasitic adult abundance annually indicated a life cycle with 1 generation per anum. There were higher numbers of adult ticks on the feet of the Angora goats than on the Boer goats. Adult numbers were higher on the hind feet of both breeds of goats than on the front feet. R.glabroscutatum adults seem to be implicated in the aetiology of foot abscesses since more infections were observed in Angora goats than in Boer goats and on the hind feet rather than the front feet within both goat groups. In addition R.glabroscutatum adults attached at interdigital sites where abscesses also originated and reached highest numbers in October and November when abscesses were most frequently observed. A review of distribution and host records indicated that R.glabroscutatum was limited in its distribution to the eastern Cape Province, being primarily located in South Africa's major mohair producing areas. R.glabroscutatum was classed an obligative xerophile on the basis of its recorded occurrence in non coastal areas with a low annual rainfall and Karoo and Karroid Bush vegetation. Host records for R.glabroscutatum included 10 species of wild ungulate, sheep, goats and cattle. The common site of occurrence on small stock and on small to medium sized wild animals appeared to be the legs and feet.

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