South African farmers have struggled for many years with the loss of livestock on their farms due to predators such as black backed jackals (Canis mesomelas) and caracal (Caracal caracal). These farmers have been known to use both lethal and non-lethal methods to control these predators on their properties. This study investigates the use of livestock guarding animals (LGAs) as a non-lethal method of controlling predators on farms. The study investigated the use of dogs, alpacas and donkeys on farms through the use of an online survey. Despite multiple appeals being sent out to different media outlets the response was modest. A structured, quantifiable and analysable questionnaire was sent to 34 farmers of whom 31 farmers completed the entire survey. The survey was used to gather information regarding the success of using these LGAs as well as the factors leading to their success and failure. There were 23 respondents who made use of dogs, eight who made use of alpacas and three using donkeys. Many studies have been done in the past on the use of dogs to protect livestock, these studies were done in Europe, the United states of America, Australia and Southern Africa. The use of both donkeys and alpacas have not been studied to the same degree. The hypothesis was that the use of LGAs (dogs, alpacas and donkeys), was successful in reducing predation by 50% or more on 75% or more of the farms surveyed. It was found that 21 of the 31 farmers who completed the survey said that predation decreased by 50% or more after acquiring a LGA. The factors leading to the success or failure in using these animals was determined for dogs, alpacas and donkeys individually. The questionnaire was designed to gather information about the farms such their size, terrain, the proximity to other farms, towns and nature reserves, and the wildlife found on the farm. We then looked at what livestock were being farmed and what LGA is being used by the farmer and how many of them are being used with the livestock. The questionnaire then went on to collect information on conception rates, lambing percentages, weaning percentages and percentages of livestock lost due to disease, predation and other factors. Looking specifically at predation we wanted to find out how much predation the farmers would attribute to which predator, how they determined which predator was responsible and how the predation changed over the time they had been using the LGA. It was also important to determine what methods of lethal control had been used previously on the farm and what was still being used by the farmers. Finally, the questionnaire covered the factors that contribute to the success and failure of the LGA as well as the cost of keeping the LGA. It was found that 33 of the 34 farmers had both sheep and cattle on their farms and only 11 farmed with goats. Nineteen of the farmers were farming on flat open plains. The farms were mostly in close proximity to other small livestock farms while others were on communal land. The number of LGAs used by the farmers were mostly determined by the size of the farm and the number of livestock. Supervision with livestock was not used by many farmers; 56% said it was unnecessary while 26% always had supervision with their animals. The rest of the farmers only occasionally had supervision with their animals. It was also found that the number of farmers making use of lethal control methods on their farms decreased from 80.65% before acquiring a LGA to 64.52% after acquiring a LGA. Predation was attributed to jackals on all farms, to caracal on 28 of the 31 farms of respondents that chose to answer this question, three farmers had problems with dogs and one farmer had predation due to leopards on his property. It was found that LGA had the greatest potential to decrease predation by jackals. The factors that were important for the use of dogs were their management, training and feeding. It was also found that dogs had the greatest financial impact on farmers as they cost more to acquire and maintain. The mean annual running cost as given by farmers was R11970.05. It was also seen that they had the greatest impact in reducing predation. The mean change in predation was 64% when making use of dogs. It was also seen that the weaning percentage on these farms increased by 25.23%. There was a change seen in the conception rate as well as the lambing percentage but neither was as large as with the weaning percentage. This is consistent with the fact that more lambs would survive if a LGA is keeping predators away. The factors that were listed as the most important factors in the use of alpacas were their temperament, the number of livestock you place with the alpaca and the age of the alpaca. The information collected on alpacas was small but showed that only four of the eight respondents saw an improvement on their properties after acquiring their alpaca. The cost of using an alpaca was not as significant as for dogs as they do not require extra housing or feed. The average running cost per annum for the use of alpacas was given as R525. There was no significant change in the conception rate, lambing percentage or weaning percentage of farmers making use of alpacas. There were only three responses for farmers making use of donkeys therefore there is no clear trend in the data but it has been reported on. The factors that were given as important were the gender of the donkey, specifically jennies (females) being more suitable, the donkey’s temperament, management and the number of livestock placed with the donkey. This was all in line with what was found in previous studies done on donkeys. Two of the three farmers using donkeys said that there was a 50% or more improvement in predation reduction on their farms. The average running cost of using a donkey was R2560 per annum. From the study it can be seen that these LGAs are successful in reducing predation but that more can still be done to encourage the use of alpacas and donkeys and to determine how successful they are. / Dissertation (MSc)--University of Pretoria, 2018. / Production Animal Studies / MSc / Unrestricted

This study evaluated eighteen commercial farms within Gauteng, Northwest and Limpopo provinces, where a representative sample of grow-out fish from each farm, was humanely euthanased, weighed, measured, and each fish’s overall health assessed through microscopic examination of skin and gills. A full necropsy and histo-pathological evaluation of all key organs followed. Farm production parameters were assessed by means of a questionnaire with a detailed history and a comprehensive water analysis that included water temperature, dissolved oxygen, CO2, ammonia, nitrite, nitrate, pH, hardness and alkalinity. These production parameters, together with stocking density and underlying nutrition, were compared with the macro- and microscopic findings for positive and negative correlations / relationships. Significantly high burdens of ecto-parasites and very poor water quality, with compromisingly low dissolved oxygen and temperatures, and high carbon dioxide and nitrite, were found in association with severe gill pathology. This was compounded by inadequate filtration for the density of fish stocked, with resultant toxic nitrogenous waste accumulation. Other key abnormalities observed were chronic-active hepatic lipid oxidation, low hepatocellular lipid, evidence of secondary opportunistic infectious disease, and extremely poor growth. Poor farm management practises were prevalent, with evidence of uneconomical fish sex ratios, and poor implementation of biosecurity and disease management. The study serves to highlight the factors that currently dominate as critical issues affecting overall health and growth of aqua-cultured tilapia in the South African context. / Dissertation (MSc)--University of Pretoria, 2019. / TM2019 / Paraclinical Sciences / MSc / Unrestricted

Increased prevalence of antimicrobial resistance, treatment failure, and financial losses have been reported in dairy cattle with coagulase-negative Staphylococcus (CoNS) clinical mastitis. However, studies on CoNS are limited in South Africa. Therefore, the objectives of this study were to investigate the antimicrobial resistance patterns and biofilm formation in CoNS isolated from cow milk samples submitted to the Onderstepoort Milk Laboratory. A total of 142 confirmed CoNS isolates were used for this study. Isolates were subjected to the tissue culture plate method for biofilm formation testing and antimicrobial susceptibility testing against a panel of 11 antimicrobials using the disk diffusion method. Biofilm formation was identified in 18% of CoNS tested. Staphylococcus chromogenes (11%) had the highest proportion of biofilm formation followed by S. haemolyticus 4.0% and S. epidermidis, S. hominis, S. xylosus, and S. simulans with 1% respectively. Ninety percent (90%) of CoNS isolates were resistant to at least one antimicrobial (AMR) and 51% were multidrug-resistant (MDR). Resistance among CoNS was the highest to ampicillin (90%) and penicillin (89%), with few isolates resistant to cefoxitin and vancomycin, 9% respectively. The most common resistance patterns among the CoNS was penicillin-ampicillin (16%) and penicillin-ampicillin-erythromycin (10%). Forty-two percent (42%) of biofilm positive CoNS were MDR. At the species level, MDR was common among S. epidermis (65%), S. chromogenes (52%) and S. haemolyticus (44%). In conclusion, biofilm formation was uncommon among the MDR-CoNS isolates in this study suggesting that biofilm formation is not a major contributing factor to antimicrobial resistance in this study. In addition, most CoNS isolates in this study were _-lactams resistant. This is concerning as penicillins are used commonly by dairy farmers in treatment of mastitis in South Africa. Nonetheless, the role of antimicrobial use practice in the development of resistance in subclinical mastitis in the dairy industry should be investigated. / Dissertation (MSc)--University of Pretoria, 2019. / Paraclinical Sciences / MSc / Unrestricted

Vermeersiekte or ‘vomiting disease’ is an economically important disease of ruminants following ingestion of Geigeria species in South Africa. Sheep are more susceptible and poisoning is characterised by stiffness, regurgitation, bloat, paresis and paralysis. Geigeria aspera was collected in the Vrede district (27° 25′ 48″ S; 29° 9′ 36″ E), Free State Province. The plant material was dried, milled and the toxic principles, known as sesquiterpene lactones, were extracted and isolated following chromatographic procedures. Even though geigerin and ivalin were previously isolated, an unknown sesquiterpene lactone, isogeigerin acetate, was also purified. Mouse myoblast (C2C12) and rat embryonic cardiac myocyte (H9c2) cell lines were exposed to different concentrations of geigerin, ivalin, isogeigerin acetate and a commercially available sesquiterpene lactone, parthenolide. An in vitro colorimetric assay 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was used to assess cytotoxicity. The median effective concentrations (EC50) indicated that ivalin and parthenolide were significantly (p<0.05) more toxic than geigerin and isogeigerin acetate. A concentration-dependent cytotoxic response was observed in both cell lines, however, C2C12 cells were more sensitive. A high performance liquid chromatography (HPLC) analysis was used to evaluate the in vitro metabolism of parthenolide, following the addition of a mouse liver microsomal fraction. Results revealed that parthenolide, incubated with the microsomal fraction, undergoes enzymatic transformation to form a metabolite. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2020. / pt2021 / Paraclinical Sciences / MSc (Veterinary Sciences) / Unrestricted

Access to international and regional markets for beef has been an on-going problem for southern African countries for many decades because the South African Territories (SAT) serotypes of foot and mouth disease (FMD) viruses are endemic to wildlife populations in the southern African region. This makes establishment of FMD-free zones, essential for accessing high-value beef markets difficult, expensive and impractical for many locations in southern Africa. For that reason commercialization of livestock production in the region has been inhibited. The creation of FMD-free zones which requires use of artificial or natural boundaries and in southern Africa it has been the construction of veterinary cordon fences (VCFs) to separate animal populations of different FMD status which has proven successful in some countries (such as Botswana, Namibia & South Africa) but not in others for a variety of reasons, i.e. the current model has only been possible for a small proportion of cattle producers in southern Africa. This means that apart from the damaging effects that some VCFs have had or have on the environment generally and wildlife conservation in particular, only roughly 15% of the cattle population in the mainland countries of the Southern African Development Community (SADC) are raised in FMD-free zones. For balanced rural development of the SADC Region, where cattle are culturally and economically vital to the indigenous inhabitants and wildlife conservation and associated economic activities are important contributors to regional gross domestic product, it is essential to improve access to regional and international markets for beef and other animal products produced in locations outside FMD-free zones. The World Organisation for Animal Health (OIE) has introduced a partially non-geographic FMD standard for trade in deboned beef (viz. Terrestrial Animal Health Code Article 8.8.22) that potentially overcomes this problem; however, Article 8.8.22 contains at least one killer requirement that makes its implementation impossible. The issues associated with this problem have been identified in this study and possible solutions proposed. An attempt was made to gauge acceptance by SADC Member States but the responses to the questionnaire used were inadequate to reach a reliable conclusion in this respect. It was concluded that taking technical, logistical and financial constraints into account, non-geographic approaches represent the best opportunity that SADC countries have of expanding access to regional and international markets. Moreover, it is suggested that non-geographic approaches could be integrated into the Standard Methods and Procedures in Animal Health (SMP-AH) Programme once adopted by SADC, thereby strengthening the capacity of the Region s competent authorities. SMP-AH Programme is at a proposal stage and has not been officially launched in SADC. The SMP AH Programme proposes to harmonize activities of animal health authorities of SADC Member States in respect of selected diseases that impact trade and/or human health. / Dissertation (MSc)--University of Pretoria, 2015. / tm2016 / Veterinary Tropical Diseases / MSc

A risk assessment was conducted for Salmonella enteritidis (SE) in the broiler production chain of the Western Cape of South Africa, using a literature review, historical data analysis, microbiological sampling from abattoirs and questionnaire responses. A questionnaire to characterise the risk pathway in the broiler chain was developed based on a review of the literature. Spatio-temporal analysis was conducted using historical data of reported SE outbreaks. The data showed spatio-temporal clustering, however, the analysis was not correct for groups of farms that form part of the same organisation. Neck skin samples were collected from five abattoirs and tested for salmonella. In total, 499 samples were collected, representing 46 broiler farms of which nine (20%) were positive. Salmonella positive cultures (2.81%) were serotyped. No SE was identified during the study. The questionnaire was completed for all stages of the broiler production chain. Significant risk factors were found using univariate analysis (Odds Ratio,OR). The significant risk factors identified by OR were further analysed using principal component analysis (PCA). The factors moving with or opposing, farm positivity were analysed using logistic regression and one layer farm was found to be a significant factor. The farms receiving eggs or chicks from that layer farm had a number of factors that were found to be significant using OR and therefore the presence of this layer farm could be a representation of these factors at the broiler farm level. SE was not identified in the samples collected from abattoirs, a number of other non-typhoidal Salmonella subspecies enterica were isolated. Given the high rates of immunosuppressive diseases within the South African population, it is important for broiler producers to be aware of the zoonotic potential of non-typhoidal Salmonella and continually improve their control measures. / Dissertation (MSc)--University of Pretoria, 2018. / Veterinary Tropical Diseases / MSc / Unrestricted

Rickettsia africae is a gram-negative bacterium which causes African tick bite fever (ATBF) in humans. ATBF is a febrile disease mainly affecting travellers to Southern Africa. This bacterium is known to be transmitted by Amblyomma hebraeum and Amblyomma variegatum ticks. In Southern Africa, the principal vector is A. hebraeum. This project was performed in a rural community in Mpumalanga province and aimed at addressing knowledge gaps of R. africae infection in A. hebraeum ticks. Infection rates in adult ticks and larvae as well as transovarial transmission efficiency of R. africae from the tick to its offspring were determined. To accomplish this, 106 adult A. hebraeum ticks were collected from cattle from Utah A and 106 from Welverdiend A. Larvae (n=1060) were collected by dragging at each of the two targeted dip tanks. Engorged female A. hebraeum ticks (n=53) were also collected from cattle from each of the two dip tanks and they were incubated in a humidity tank to oviposit and egg masses were collected from each tick. DNA was extracted from the engorged ticks and the egg masses as well as from the adult ticks and the larvae. After DNA quantification, a real-time quantitative PCR targeting Rickettsia gltA gene was performed to screen all samples for Rickettsia DNA. The gltA gene is common in all Rickettsia species. Samples positive for the gltA gene were subjected to conventional PCR targeting the ompA gene, which is specific for the Spotted Fever Group to which R. africae belongs. The samples positive for amplicons of ompA gene were sequenced and all the sequenced samples were found to be 99.98% identical to R. africae sequences from GenBank. From the sampled adult ticks, 13.43% tested positive for R. africae and 13.20% of the larvae also tested positive. The infection rate for larvae and adult ticks collected from Utah A was 15.09% and those from Welverdiend A was 11.79%. From these results, there were no notable differences in the infection rates of ticks at different stages of development. R. africae infection rates for the two study sites were found to be similar which can be an indication of even distribution of R. africae in this area. Transovarial transmission was found to be 100% in engorged female ticks collected from Utah and 71.43% in ticks from Welverdiend, which indicates a high transmission rate of the pathogen to the offspring of the vector. The presence of R. africae in A. hebraeum ticks from this area is a cause of concern since there are chances of people getting ATBF after bites by these ticks. / Dissertation (MSc)--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc / Unrestricted

In the Bushbuckridge Local Municipality (BLM), Mpumalanga, the size and economic importance of the local, mostly informal, cattle trade has been considered negligible to date by local policy makers. Opportunities for the local cattle farmers to access formal live or product markets remain severely limited, mainly as a result of movement restrictions associated with foot-and-mouth disease (FMD) control. Data, in the form of movement permits and monthly cattle registers were used to analyse movement and trade activity in the area over a four-year period (May 2015 - April 2019). The population fluctuated around 77 166 head of cattle, distributed between 9739 emerging rural livestock farmers. The proportion of animals/products moved ranged between 3.1 and 7.2 percent (0.04 ± 0.02). Movements were found to be highly seasonal (p < 0.001) with the ‘cool dry’ season (April-July) being the most active. Most movements consisted of live cattle which were herded to their destinations. The vast majority of trade did not leave Bushbuckridge and was informal in nature. Farmers moved animals and products much further to access formal markets (p < 0.001) than informal markets, and generally required use of motorised transport to do so. The FMD outbreak of 2017 did not prove detrimental to the local cattle industry in the medium term. However, distinct changes to the overall Bushbuckridge herd dynamics were noted, with small scale farmers most severely affected. As a direct result of the heightened movement restrictions in this period, an estimated 96% of formal trade; 85% of informal trade, and 54% of local trade were lost. In 2018, an improvement in cattle prices stimulated farmers to access the formal marketplace, and an increase in the proportion of the cattle population moved was observed. It was concluded that farmers pursue formal marketing options only when financially incentivised or pressurised by adverse conditions such as environmental factors or disease outbreaks. Growing established local markets is likely the best way to assist the local population with market access, development and poverty reduction. The key constraints to marketability of animals/products originating in the BLM were identified as the absence of a competitive market system and associated infrastructure such as FMD designated abattoirs, disease control regulations, poor carcass quality, and seasonality of offtakes. These limitations will need to be considered when policy decisions are made. Context-specific solutions should be generated to address local needs and effectively support development of a sustainable cattle trade going forward. / Mini Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Unrestricted

Rift Valley fever virus (RVFV) is a mosquito-borne virus and a member of the family Phenuiviridae and genus Phlebovirus. The single stranded RNA genome consists of three segments, Large (L), Medium (M) and Small (S). Rift Valley fever (RVF) is a mosquito-borne zoonotic disease that may cause large epidemics in ruminants and humans. Infection in humans causes influenza-like symptoms but the disease can also be more severe and fatal. Outbreaks in livestock are classified by abortion storms and young and newborn animals are severely affected with a high mortality rate. Rift Valley fever causes severe health and economic consequences in the areas where it occurs. Since the first recorded incidence of RVF in Kenya in 1930, South Africa has had three major countrywide outbreaks: in 1950-1951, 1973-1975 and 2008-2011. The disease is characterized in southern Africa by large epidemics at long, irregular intervals. The epidemics are usually associated with conditions favourable for proliferation of mosquito populations, such as high rainfall and flooding. Rift Valley fever has previously been isolated from 12 different mosquito species in South Africa including 5 Aedes spp., 3 Culex spp., 3 Anopheles spp. and 1 Eretmapodites sp. The presence of the virus and patterns of occurrence of the disease in the eastern parts of South Africa are poorly understood. Multiple studies were conducted; the aim of the first study was to detect the presence of RVFV in far northern KwaZulu-Natal Province, South Africa and to estimate the incidence rate of seroconversion. Cross-sectional studies were performed in communally farmed cattle (n=423) and goats (n=104), followed by longitudinal follow-up of seronegative livestock (n=253) 14 times over 24 months, representing 160.3 animal-years at risk. Exposure to RVFV was assessed using an IgG sandwich ELISA and a serum neutralization test (SNT) and seroconversion was assessed using SNT. Initial overall seroprevalence was 34.0% (95%CI: 29.5-38.8%) in cattle and 31.7% (95%CI: 22.9-41.6%) in goats, varying by locality from 18-54%. Overall seroconversion rate in cattle was 0.59 per animal-year (95% CI: 0.46-0.75) and in goats 0.41 per animal-year (95% CI: 0.25-0.64), varying significantly over short distances. The high seroprevalence in all age groups and evidence of year-round viral circulation provide evidence for a hyperendemic situation in the study area. The second study investigated the seroprevalence and associated risk factors of RVFV in antelope in the Tembe Elephant Park (TEP) and the Ndumo Game Reserve (NGR), using 326 sera from nyala (Tragelaphus angasii) and impala (Aepyceros melampus) routinely culled over a two-year period. The overall seroprevalence of RVFV was 35.0% (114/326; 95% CI 29.8-40.4%); the presence of antibodies in juveniles (6/21; 28.6%; 95% CI 11.3-52.2%) and sub-adults (13/65; 20.0%; 95% CI 11.1-37.8%) confirmed that infections had occurred subsequent to the 2008-2011 RVF outbreaks in South Africa. Seroprevalence was highest in adults and inversely associated with distance from a swamp or floodplain. The third study aimed to investigate the diversity, abundance, and seasonal dynamics of mosquitoes in the study area, and to screen mosquitoes for RVFV. Monthly collections of adult mosquitoes were carried out from January 2017 to June 2018 at three sites using CO2-baited tent traps. Mosquitoes were identified, pooled and screened for RVFV by quantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) directed toward amplification of a 217-bp fragment of the L segment. A total of 34,848 mosquitoes of 7 genera and 48 species, were captured; Culex (Cux.) tritaeniorhynchus (31%), Cx. (Cux.) antennatus (29%), Aedes (Adm.) durbanensis (12%) and Cx. (Cux.) neavei (10%) were the most abundant species collected. Genera differences were noted between the collection sites. Cumulative rainfall and average minimum temperatures 30 days prior to collection were positively associated with the number of mosquitoes collected while maximum temperatures were only associated with the number of Culex mosquitoes caught. A single pool of Ae. durbanensis was found to be positive for RVFV genomic RNA. The same pool was also positive for Chikungunya virus (Family Togaviridae, genus Alphavirus) (CHIKV) and Sindbis virus (Family Togaviridae, genus Alphavirus) (SINV). The RVFV isolate was closely related to one obtained from Ae. (Neo.) circumluteolus at Simbu pan in 1955, ±20 km from the collection sites for this study. Further investigation should be done on the human health implications of the presence of these three zoonotic arboviruses. It is possible that these viruses are causing disease among the communities in the area and that the diseases are under-reported. The results of this study show that RVFV is circulating in the area in domestic ruminants and wildlife, in the absence of apparent clinical disease, at a rate that varies by location, season and year. It appears that, under similar ecological conditions, domestic and wild ruminants may play a similar role in maintenance of viral circulation, and either or both may serve as the mammalian host in a vector-host maintenance system. The study also demonstrates the presence of a wide variety of mosquito species, several of which are known to be competent RVFV vectors. / Thesis (PhD)--University of Pretoria, 2019. / Veterinary Tropical Diseases / PhD / Unrestricted

Ticks and tick-borne diseases (TBDs) cause significant losses, through their effects on health, production of animals and humans worldwide. Notably, the countries located within the tropics and subtropics such as Uganda are the most affected due to abundance and distribution of the tick vector. Unfortunately, there is little data in Karamoja Region regarding tick species and the pathogens they transmit. Therefore, a cross-sectional study was undertaken to determine the various tick species, and to detect the tick-borne pathogens within the ticks collected from cattle in Karamoja Region, northeastern Uganda. Between June 2017 and early September 2017 (wet season), a total of 4,897 ixodid ticks were collected from 100 cattle in 20 purposively-selected herds. Three genera of ticks, namely Amblyomma (96.8%), Hyalomma (0.6%) and Rhipicephalus (2.6%) were identified. From the ticks collected, the most dominant species was A. lepidum (93.85%), followed by A. variegatum (2.0%), R. evertsi evertsi (1.0%) and A. gemma (0.98%). Tick species that have not been reported in recent studies in Uganda were found amongst cattle in Karamoja, and these were R. pravus, R. praetextatus and R. turanicus. A representative number of ticks, from each tick species identified in the present study were placed in pools of 1 to 10. Subsequently, a reverse line blot (RLB) hybridization assay was performed to screen for the presence of tick-borne pathogens. Out of the 40 tick pools, 30 (75%) were positive for tick-borne pathogens of the genera Ehrlichia, Anaplasma, Babesia and Theileria. The RLB assay results showed that 57% (n=17) of the tick pools were positive for single infections, while 43% (n=13) had mixed infections. The most frequently detected tick-borne pathogens were T. parva (10 pools), T. velifera (10 pools), T. mutans (9 pools) and Theileria sp. (sable) (5 pools). Other pathogens detected were E. ruminantium, B. microti, B. rossi, T. separata and B. bigemina. The tick-borne species B. microti, B. rossi, Theileria sp. (sable) and T. separata are not common in cattle, or not known to infect cattle, but were detected from the ticks collected. The detection of B. microti in this study may point to incidental infections with implications for human health. There could have also been a possibility of cross reactions during the RLB analysis leading to the detection of B. microti in this study. These findings provide knowledge of the distribution of ticks and epidemiology of tick-borne pathogens in cattle and may provide support for control of TBDs and improve cattle productivity. / Mini Dissertation (MSc (Tropical Animal Health))--University of Pretoria, 2019. / Veterinary Tropical Diseases / MSc (Tropical Animal Health) / Unrestricted