Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 364-373). Also available on the Internet.

Thesis (Ph.D. International Global Change Institute (IGCI))--University of Waikato, 2007. / Title from PDF cover (viewed April 7, 2008) Includes bibliographical references (p. 291-320)

Six livestock owners, who are commonly used as demonstrators, participated in the study of which three were from communal areas and three from freehold farms in the Ganyesa area. The livestock production potential in communal areas was compared with that of freehold farms. Information on livestock production, veld condition, Dry matter, crude protein- content of natural grasses and extension services were determined and evaluated for each study area. The result of this study revealed that because of variation in climate, Ganyesa is classified as semi- arid and is mainly suitable for livestock production. The result further revealed that there were major constraints in livestock production in the study area and these were related to land tenure system and poor livestock production. In both communal areas and freehold farms, farmers were unable to invest in infrastructural development and this immensely affected production, and led to over-grazing. The performance of the herds (calving %) in communal areas was low (54%) as compared to that on the freehold farms (6 %). However, the results revealed that more calves that were born lived up to weaning (85% in communal areas, 90 % on freehold farms) and this compared favourably with results from other areas. Herd mortality rates for both communal (2%) and freehold farms (2%) were reported to be low. The performance of smallstock was somehow lower than expected for both communal and freehold farms. The lambing kidding percentage was low (62% and 69%, respectively) and mortality rates were somewhat high (to % and 23% respectively). This means that many lambs/kids died due to diseases and malnutrition and thus did not reach a weaning age. Forage DM production was reported to be higher on freehold farms than in communal areas, and this supported the argument that the latter areas are over-stocked. The CP¬content of forage was high for freehold farms during December - January and low during July - August. The CP -values of forage for freehold farms were higher than those for communal areas with the highest figures recorded during January. The veld condition score was reasonable on freehold farms with a high percentage of desirable grass species (28 % ) and low in communal areas (22 %) with high percentage of undesirable grass species (52 %) recorded by the latter. The results of this study revealed that all samples recorded high strontium (Sr) values, indicating likely contamination of the borehole sites. The high levels of titanium (Ti) and barium (Ba) on freehold farms may indicate a possibility of industrial pollution of boreholes. Most of the water sources sampled may also be utilised by humans for drinking, food preparation and drinking purposes with detrimental effects. In view of these constraints, some recommendations were made. / Dissertation (M Inst Agrar (Animal Production))--University of Pretoria, 2005. / Animal and Wildlife Sciences / unrestricted

Livestock production is the primary financial resource for most farmers in Mpumalanga province. Although commercial farmers require necessary equipment and technology to maximise their production and profit, but emerging small-scale farmers in the province face many challenges which have hindered their efforts to improve their livelihood, besides intervening in the procedure of commercialisation. Therefore, this study investigates the socioeconomic characteristics of the livestock farmers in the province, the determinants of market access and those influencing marketing inefficiency, with a view to developing policy recommendations. Structured questionnaire was administered to 300 farmers in order to capture information on market access and factors that could influence marketing inefficiency. Descriptive statistics was utilised regarding basic characteristics of the households. A logit regression model was used to analyse market access (sale of livestock through formal markets) using STATA. Marketing inefficiency was computed as the reciprocal of marketing efficiency which was calculated using Shepherd formula, while the two stage Least Square regression was applied for factors influencing marketing inefficiency after identifying market access endogenous variable. The study’s extrapolations indicated that 7 variables were consequential at 1% and 5% significance level with market access, namely transport ownership, transport cost, market price information, advertisement, farmers’ perception, marketing channel used and municipality. In addition, the results of the two stage least square model indicated that only 3 variables had remarkable significance with regard to marketing inefficiency. These are market access, livestock composition and infrastructure. The findings of the study evidenced that to reduce marketing inefficiency, then it is paramount to enable the easy dissemination of information and improving infrastructure so as to give small-scale farmers easy access to the markets. Consequently, addressing marketing constraints will provide an insight that will allow development of strategies to deal with those problems correctly and more efficiently. The study recommended that focus should be centred on addressing the constraints existing in livestock marketing system to enhance access to markets by encouraging youth participation in agricultural activities and providing training programmes and easy access for marketing related information. Also, infrastructure deserves to be given more attention by renovating the marketing facilities especially road networks in rural areas. In addition, extension officers and veterinary services are to provide help and support in preventing infections and diseases in order to minimise the losses. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

Trypanosoma congolense is a protozoan parasite transmitted by tsetse flies. It causes bovine trypanosomosis, the major disease for livestock in sub-Saharan Africa. Control methods include trypanocidal drugs and vector control, but none is fully satisfactory, due to resistance and environmental issues. A method that would have the greatest impact on controlling the disease is vaccination. However, development of a conventional vaccine has been hampered by the mechanism of antigenic variation, which allows the parasite to evade the host’s immune system. An alternative strategy in vaccine design is to target the bioactive compounds released by dead and dying trypanosomes. This approach is termed ‘‘anti-disease’’, and does not affect the survival of the parasite but targets the pathogenic factors released by the trypanosomes. The development of a successful anti-disease vaccine necessitates knowledge of all pathogenic factors involved in the disease process. Several macromolecules, primarily peptidases, have been implicated in the pathogenesis of trypanosomosis. Pyroglutamyl peptidase type I (PGP) was shown to be involved in abnormal degradation of thyrotropin- and gonadotropin-releasing hormones in rodents infected with T. brucei, but to date no data are available on the T. congolense PGP. Molecular cloning and expression in E. coli of the coding sequence of T. congolense PGP, as well as the enzymatic characterisation of the recombinant protein, are reported here, completed by the development of reverse genetics tools for studies of gene function. A 678 bp PCR fragment covering the complete open reading frame of PGP was cloned and sequenced. The deduced amino acid sequence showed 52% and 29% identity with the T. brucei and Leishmania major enzymes respectively. The catalytic residues Glu, Cys and His described in Bacilus amyloliquefaciens PGP are conserved in the T. congolense sequence. PGP was expressed in bacterial systems as a soluble active, 26 kDa enzyme. The recombinant enzyme showed activity specific for the fluorescent substrate pGlu-AMC, with a kcat/Km of 1.11 s-1μM. PGP showed activity in the pH 6.5-10 range, with maximal activity at pH 9.0. The enzyme was strongly inhibited by sulfhydryl-blocking reagents such as iodoacetic acid and iodoacetamide with a kass of 125 M-1 s-1 and 177 M-1 s-1 respectively. Antibodies raised in chickens against the recombinant enzyme allowed the detection of native PGP in both procyclic and bloodstream T. congolense developmental stages, and displayed complete inhibition of the enzyme in vitro at physiological concentrations. To get insight into the role of PGP in parasite biology and trypanosomosis progression, two types of vectors for reverse genetics studies were developed. For RNA interference, a 400 bp 3′ end segment of the PGP open reading frame was cloned into the plasmid p2T7Ti, that will allow PGP gene down-regulation upon integration into the genome of an engineered tetracycline-inducible strain such as TRUM:29-13. For gene knock-out, several rounds of molecular engineering were carried-out in order to create two plasmid vectors, pGL1184-based (blasticidin resistance) and pGL1217-based (neomycin resistance), each bearing 200 bp-long regions at the 5′ and 3′ ends of the PGP open reading frame. In subsequent studies, taking advantage of the recent advances in culture and transformation of T. congolense, these plasmids will allow the creation of single and double knock-out mutants of PGP. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Within the field of pattern recognition (PR) a very active area is the clustering and classification of multispectral data, which basically aims to allocate the right class of ground category to a reflectance or radiance signal. Generally, the problem complexity is related to the incorporation of spatial characteristics that are complementary to the nonlinearities of land surface process heterogeneity, remote sensing effects and multispectral features. The present research describes the application of learning machine methods to accomplish the above task by inducting a relationship between the spectral response of farms’ land cover, and their farming system typology from a representative set of instances. Such methodologies are not traditionally used in crop-livestock studies. Nevertheless, this study shows that its application leads to simple and theoretically robust classification models. The study has covered the following phases: a)geovisualization of crop-livestock systems; b)feature extraction of both multispectral and attributive data and; c)supervised farm classification. The first is a complementary methodology to represent the spatial feature intensity of farming systems in the geographical space. The second belongs to the unsupervised learning field, which mainly involves the appropriate description of input data in a lower dimensional space. The last is a method based on statistical learning theory, which has been successfully applied to supervised classification problems and to generate models described by implicit functions. In this research the performance of various kernel methods applied to the representation and classification of crop-livestock systems described by multispectral response is studied and compared. The data from those systems include linear and nonlinearly separable groups that were labelled using multidimensional attributive data. Geovisualization findings show the existence of two well-defined farm populations within the whole study area; and three subgroups in relation to the Guarico section. The existence of these groups was confirmed by both hierarchical and kernel clustering methods, and crop-livestock systems instances were segmented and labeled into farm typologies based on: a)milk and meat production; b)reproductive management; c)stocking rate; and d)crop-forage-forest land use. The minimum set of labeled examples to properly train the kernel machine was 20 instances. Models inducted by training data sets using kernel machines were in general terms better than those from hierarchical clustering methodologies. However, the size of the training data set represents one of the main difficulties to be overcome in permitting the more general application of this technique in farming system studies. These results attain important implications for large scale monitoring of crop-livestock system; particularly to the establishment of balanced policy decision, intervention plans formulation, and a proper description of target typologies to enable investment efforts to be more focused at local issues.

The work presented in this thesis is focused upon the community of endemic pathogens of African cattle in Sub-Saharan Africa, which has long constrained livestock production in these areas. The first aim of this work is to investigate whether the pathogen community as a whole shapes the ensuant epidemiology and morbidity which are currently attributed to any of its individual pathogens. The second aim is to determine if a greater understanding of the interactions present amongst genetically distinct parasites of the same species can be used to better explain epidemiological features that are at present poorly understood. Emphasis is placed on examining spatial variation in the epidemiology of Theileria parva, a tick-transmitted protozoan that causes East Coast Fever. To achieve these aims, this work examines field data collected from a large and comprehensive study conducted in south east Uganda. Through application of apposite statistical techniques and mathematical modelling, aspects of the complex relations amongst the pathogen community and their environment are explored. Evidence is presented that demonstrates the paramount role of the pathogen community as a whole in shaping the infection dynamics and pathogenicity of any of its individual components. By focusing on a single member of this pathogen community (Theileria parva), some of the influences of host, vector, geographical location, temporal dynamics and intra-species pathogen interactions are elucidated. Application of a polymorphic molecular marker to Theileria parva infected blood samples and the use of Cox proportional hazard analysis, show variability in the survival of infections in cattle in high and low tick challenge areas. Moreover infection survival, which plays a pivotal role in parasite transmission, is shown to be a function of the interactions established amongst genetically distinct co-infective parasites. In consequence, vector intensity alone is insufficient to develop reliable transmission models which can accurately predict the epidemiology of the parasite inside and outside enzootic belts. Finally, a theoretical model is developed which, based upon the field evidence obtained throughout this work, provides a possible explanation for the mechanics of T. parva survival in cattle. In summary, this thesis makes a case that consideration of both inter- and intra-species pathogen interactions, can greatly augment understanding of the epidemiology of these pathogen communities. An integrated approach to pathogen dynamics can better equip an integrated approach to control of important diseases of African cattle.

Within the last decade antibiotic resistant bacteria have become a major public health concern. A possible major contribution to this problem is thought to be the overuse of antibiotics in food animals. An estimated 70% of antibiotics dispensed yearly throughout the United States are distributed to the livestock industry as growth promoters, prophylactic, and therapeutic treatments, according to the Center for Disease Control and FDA. When food animals are exposed to low doses of antibiotics frequently over a long period of time the bacteria are able to develop resistance to antibiotics. Livestock harbor foodborne pathogens that are generally commensal bacteria in the animals themselves but can cause illness to the people exposed. The problem occurs when treatment becomes difficult, there is some speculation that livestock animals are a main contributor to the increase in antibiotic resistant foodborne pathogens. Salmonella spp. and Staphylococcus aureus are pathogens that can be isolated from livestock and cause serious illness in humans. Objectives of this study include isolating S. aureus and Salmonella from samples collected from food animals, investigating the prevalence of antibiotic resistance in the confirmed S. aureus and Salmonella isolates from animals raised in various areas of Southern New Mexico and Arizona. In this study, samples were collected from various food animals post-harvest at a USDA inspected, non-commercial animal harvest facility in Arizona, and evaluated for the presence of S. aureus and Salmonella. Samples were collected from 129 animals of the following types: Bovine (cow), Caprine (goat), Ovine (sheep), and Porcine (pig). S. aureus and Salmonella were isolated from three different types of samples per animal including hide samples, sub iliac and mesenteric lymph nodes, and nasal swabs. Each sample was cultured separately in enrichment media followed by selective/differential media. Once the pathogen was confirmed via 16s rRNA PCR for S. aureus, invA3 PCR for Salmonella, gel electrophoresis, DNA Sequencing, and other biochemical tests, an antibiotic susceptibility test was performed to check the resistance characteristics of each isolate. The pathogen was exposed to eight different antibiotics- Ampicillin, Cefoxitin, Chloramphenicol, Ciprofloxacin, Erythromycin, Streptomycin, Sulfamethoxazole/Trimethoprim, and Tetracycline; commonly used among animals and humans via the disc diffusion assay. A total of 59 and 60 of 369 samples were confirmed positive for S. aureus and Salmonella, respectively. The animal type that harbored the most Salmonella overall were Bovine/cattle and the sample type that harbored the most Salmonella overall were lymph nodes. The animal type that harbored the most S. aureus overall were porcine/pigs and the sample type that harbored the most S. aureus overall were lymph nodes. 18 out of 129 livestock animals sampled in this study were found to carry both Salmonella and S. aureus and were isolated from: 6-Porcine, 5-Bovine, 5-Caprine, and 2-Ovine. The overall antibiotic resistance prevalence in S. aureus and Salmonella were 22.88% and 32.71%, respectively. Antibiotic resistance patterns were seen in both S. aureus and Salmonella isolated from all different livestock and sample types. Of these S. aureus isolates 43 showed resistance to at least one type of antibiotic, and the most resistance was seen to Ampicillin. 53 Salmonella isolates showed resistance to at least one type of antibiotic, and the most resistance was seen to Erythromycin. The implications of this study indicate that there are antibiotic resistant Staphylococcus aureus and Salmonella found in various food animals and sample types. Most of these Salmonella and S. aureus isolates were resistant to more than one antibiotic. Appropriate control measures are needed to mitigate the problem of antibiotic resistant bacteria among food animals. These control measures could also reduce the spread of resistance from one bacterium to another and possibly lessen the antibiotic resistance problem and infections.

Philosophiae Doctor - PhD / Springs are an important natural resource in many rural spaces which, if utilised sustainably, can be an important source of livelihoods for rural communities. In Zimbabwe, the social aspects of springs and their waterscapes remain understudied. This includes an in-depth understanding of how communities have shaped their livelihoods around springs, the extent to which they have contributed to sustainable rural livelihoods, especially in water stressed parts of the country and the institutional framework shaping their access and utilisation. Using the sustainable livelihoods framework of analysis, the goal of this study was to investigate the role that springs and their resultant waterscapes have played in securing livelihoods for rural households in the Save Catchment of Zimbabwe. Methodologically, the research adopted the socio-hydrological approach which is a new and emerging discipline that aims at understanding the interactions and feedbacks between the human and natural processes that give rise to community water sustainability challenges. The socio-hydrological approach is informed by both the qualitative and quantitative research techniques of data collection and analysis. Two rural communities (Nyanyadzi and Maturure) of the Save Catchment were randomly selected for an in-depth study. The snowball sampling technique (non-probability) was utilised in the selection of the 100 participants for the questionnaire survey. Purposive sampling was used to select nine key informant interview participants. Secondary data collection was done through a systematic review of scholarly and policy literature. Qualitative data generated from primary and secondary sources were processed and analysed using qualitative techniques such as thematic ordering, systematisation and fine grain analysis. For quantitative data, descriptive statistics, such as frequencies, were used to summarise and analyse questionnaire data. Rural communities in the Save Catchment of Zimbabwe were observed to have developed livelihood strategies that were anchored on springs and their waterscapes. In the studied communities, springs were utilised for both commercial and subsistence purposes and livelihoods constructed around springs included; gardening, tourism, livestock production, brick kilning art and craft making. In the study, springs were also shown to be a very important component of sustainable rural livelihoods. However, most of them were perceived to be declining in both water quality and quantity, imposing complex livelihood conundrums for the rural communities and threatening the sustainability of livelihood strategies that they are supporting. Practices observed to be threatening the integrity of springs were encroachment of settlements, natural environmental changes, soil erosion and population pressure. Limited environmental awareness, poverty, poor implementation and enforcement of conservation laws has resulted in the adoption of practices that degraded springs. Institutions shaping spring utilisation were observed to be ineffective to a large extent due to lack of capacities and conflicting mandates but local traditional leadership and water committees were observed to have deeper community penetration and were the most effective in influencing access and effective management of springs and their related waterscapes.

Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / Small ruminants found in pastoral dryland systems face many challenges regarding constant environmental and climate changes. These variable environments are home to many pastoralists who use the natural resources to sustain their livestock. Due to the prevailing environmental changes, these pastoralists require various adaptation strategies for the survival of their small ruminants. Adaptation is vital for all pastoralists globally, especially those living in semi-arid to arid regions as these areas are badly impacted by climate change. Farming with small ruminants that are able to constantly adapt to variable environments are a long-term and low cost resource strategy for farmers in these areas. Drought is a recurring challenge that farmers in dryland systems have to cope with and small ruminants are forced to adapt to food and water available to them as drought affects their survival, reproduction and production. This is because drought affects the environment directly as rainfall has an impact on all forage and water resources found in drylands. Thus available forage and the utilisation of this resource by small ruminants is essential for sheep and goat farmers who depend on these animals for their livelihoods. This thesis sets out to establish sheep and goat breeds found in a dryland pastoral system in South Africa focussing on their genetic differences and their diet selection during a drought period. The study was carried out in the 582 634 ha Steinkopf communal area located in the semi-arid to arid region of Namaqualand in South Africa. The dominant land use in this area is livestock farming where farmers utilise two biomes for grazing. Using mitochondrial DNA, genetic differences were investigated in small ruminants found in Steinkopf. The small ruminants that were studied were the Boer goats, Swakara sheep (Karakul) and cross-bred sheep. These were the most commonly farmed small ruminants in this area. Genetic differences and diversity found within the small ruminants in this area supports their ability to adapt to drought and changing environments. Diet selection of these small ruminants were assessed using direct forage observation during this drought period in both the Succulent and Nama Karoo biomes. Findings of the study indicate that small ruminants during a drought period will largely forage on what is available to them. Boer goats changed their diets from browser to grazers in the different biomes while sheep remained grazers in both biomes. This suggests that these animals are well adapted to changing forage availability and will adjust their feeding behaviours accordingly. Succulent plant species were utilised by all small ruminants and this can be regarded as new knowledge for small ruminants in dryland systems. Succulent species play a role in the diets of small ruminants in the Steinkopf rangeland and these animals have adapted traits that allow them to eat plants that contain high levels of phenolics and tannins, which show their high adaptability to this area. This study also revealed that indigenous and locally bred sheep in this area are crucial resources for livestock farming in this area. Swakara sheep in this area showed a low level of genetic variation while cross-bred sheep and the Boer goat had significant variation. With a long tradition of breeding small ruminants in the Steinkopf communal area that suit changing conditions, livestock keepers have accumulated detailed knowledge of their animals. Recommendations from this study were to do further studies regarding genetic variation within the cross-bred sheep as this information will be useful for breeding programs in dryland areas and it will add to the small ruminant genetics in South Africa. Because this study was conducted in a drought period, I recommend that diet selection should be observed during a regular wet and dry period as this would indicate how these animals adapt to what forage is available to them. These studies can act as management strategies for herders as it can provide information on how to use the natural resources sustainably.