No description available.

No description available.

Extensive emphasis on selection for milk yield with minimal attention to the animals' functional performance has increased the yield of North American dairy cattle. The high intensity of selection for production traits such as milk yield, protein yield and fat yield has also brought about a rapid increase in genetic relationships among animals. In dairy cattle, correlated response to selection for milk yield includes fertility and susceptibility to diseases. Although the high producing cows have greater net profit, they also have higher mammary and discarded milk costs associated with high production. Long-term genetic selection against clinically diagnosed diseases might be useful to diminish their incidence. The Scandinavian countries have incorporated the health traits into their selection indices. Canadian breeding programs realize the need to consider traits other than the yield in selection decisions. The objective of this study was to determine the genetic variability of various clinically diagnosed health traits. Data from 171 herds of the Ontario milk-recording program were used. These herds are collaborating with the University of Guelph (Dr. David Kelton) to record health traits. A major impediment to estimating heritabilities for the majority of the disorders was that the progeny group size per sire was not large enough to enable detecting a significant difference among sires. Hence, heritability estimates were not obtained for all the health disorders included in the study. The progeny group size per sire has to be increased such that there are at least 5 cases per progeny group to enable detecting a difference among sires. Heritability estimates for retained placenta and displaced abomasum in the first lactation were 0.067 and 0.212 respectively. The heritability estimate of cystic ovaries in the second lactation was 0.092. In the third lactation, the heritability estimate of mastitis was 0.10 whereas retained placenta had a heritability of 0.25.

Made available in DSpace on 2014-06-11T19:31:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-27Bitstream added on 2014-06-13T20:22:03Z : No. of bitstreams: 1 cavalcante_gg_dr_botfmvz.pdf: 628746 bytes, checksum: 0fafde3beb2bdbf9dafb4f6b57c8b09e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A dinâmica das infecções naturais por Babesia bovis, Babesia bigemina e Anaplasma marginale, foi investigada ao longo do primeiro ano de vida de bezerros da raça Nelore criados em sistema extensivo no Estado de São Paulo, com o propósito de se avaliar a influência da criação exclusiva e extensiva de bovinos da raça Nelore sobre a epidemiologia desses hemoparasitas. Amostras de sangue de 17 animais P.O. foram colhidas a cada 15 dias do nascimento até os quatro meses, e então, a cada 30 dias até um ano. Amostras de sangue colhidas da ponta da orelha foram utilizadas para a confecção de esfregaços sanguíneos, e amostras de sangue da veia jugular foram utilizadas para a determinação da contagem total de eritrócitos (RBC), concentração de hemoglobina (HB), volume globular (VG), contagem total de leucócitos (CTL) e extração de DNA. As teleóginas colhidas foram incubadas em estufa BOD e posteriormente submetidas ao processo de extração de DNA. A amplificação do DNA dos hemoparasitas foi feita pelas técnicas de PCR e nPCR, utilizando-se respectivamente os primers BoF e BoR; BoFN e BoRN para Babesia bovis, BiIA e BilB; BilAN e BilBN para B. bigemina e Am9 e Am10; Am11 e Am12 para A. marginale. Ao longo de um ano de experimento não foram observados casos clínicos de tristeza parasitária, e os quatro animais em que parâmetros hematológicos indicativos de anemia foram detectados concomitantemente com uma ou mais espécies de hemoparasitas se recuperaram sem que houvesse necessidade de tratamento. Babesia bovis não foi detectada nos esfregaços sangüíneos corados por Giemsa, porém merozoítas de B. bigemina foram encontrados em 5 amostras de sangue provenientes de 4 animais. Corpúsculos intraeritrocitários de A. marginale foram detectados em 29 amostras oriundas de 14 animais, nas quais a mais elevada taxa de parasitemia foi de 26%... / The dynamics of natural Babesia bovis, Babesia bigemina and Anaplasma marginale infection was investigated along the first year of Nelore calves, raised on extensive system in São Paulo State. The purpose was to evaluate the influence of the exclusive and extensive breeding of Nelore bovine on the epidemiology of those hemoparasites. Blood samples of 17 purebred animals were harvested every 15 days beginning on the first day of birth till four months old, and then, every 30 days till one year old. Blood samples from the ear tip were used to made blood smears, and blood samples were taken from the jugular vein to determine the red blood cells total count (RBC), hemoglobin concentration (HB), haematocrite (VG), leukocytes total count (LTC) and DNA extraction. The engorged Boophilus microplus were incubated and submitted to the DNA extraction process. The hemoparasite DNA amplification was made by PCR and nPCR respectively, using the primers BoF and BoR; BoFN and BoRN for Babesia bovis, BiIA and BilB; BilAN and BilBN for B. bigemina and Am9 and Am10; Am11 and Am12 for A. marginale. Clinical cases of parasitic sickness were not observed along one year of experiment. The four animals that were observed with indication of anemia hematological parameters, detected at the same time with one or more hemoparasites species, recovered without treatment. Babesia bovis was not detected in the blood smears. However, B. bigemina merozoites were found in five blood samples coming from four animals. A. marginale was detected in 29 blood samples of 14 animals, in which the highest parasitemia level was 26%. The reactions of PCR and nPCR revealed the presence of B. bovis DNA in seven blood samples (four by PCR) from three animals, one of them born in less than 24 hours... (Complete abstract, access undermentioned electronic address)

Made available in DSpace on 2014-06-11T19:35:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-12-21Bitstream added on 2014-06-13T19:24:34Z : No. of bitstreams: 1 hellu_jaa_dr_jabo.pdf: 1300043 bytes, checksum: fd291aaeaf8c8b4e70e0f65e0dc05a6e (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No final da década de 1990 observou-se um aumento significativo de uma nova modalidade de afecção, o prolapso vaginal parcial ou total recorrente não associado à gestação, principalmente em vacas zebuínas. Em razão do alto valor comercial dos animais acometidos, inicialmente, indicou-se as técnicas convencionais como as de Caslick, Bühner ou Flessa, porém sem o sucesso esperado devido à recorrência da alteração. Considerando esta dificuldade, este trabalho objetivou descrever duas novas técnicas cirúrgicas na correção do prolapso vaginal, denominadas vaginectomia parcial e vaginopexia dorsal em vacas. A condução do estudo foi a campo, utilizando-se 812 vacas zebuínas em idade reprodutiva, alojadas em diversas propriedades de diferentes estados brasileiros. Foram selecionados animais que apresentavam a afecção e que mantiveram os parâmetros clínicos de frequência cardíaca, frequência respiratória e temperatura retal, dentro da normalidade. O diagnóstico do prolapso vaginal foi realizado por meio de anamnese e dos sinais clínicos como exposição da vagina pela rima vulvar, tenesmo, inquietação, lesões da porção evertida, retenção urinária e vaginite. A avaliação dos animais permitiu definir o estágio do prolapso, com a finalidade de eleger a técnica cirúrgica mais adequada. Os protocolos anestésicos foram cumpridos, considerando-se a técnica cirúrgica eleita. A vaginectomia parcial foi utilizada para o tratamento do prolapso vaginal de grau 1 e a vaginopexia dorsal para os de grau 2 e 3. Os resultados pós-cirúrgicos das duas técnicas indicaram alta porcentagem de recuperação (93.44% para vaginectomia parcial e 96,14% para vaginopexia dorsal) e baixo número de recidivas (6,25% e 3,66%, para vaginectomia parcial e vaginopexia dorsal, respectivamente, e baixa mortalidade (entre 0,20 a 0,31%), podendo... / At the end of the decade of 1990, a significant increase of a new affection was observed in the field. This occurrence, recurrent partial or total vaginal prolapse is not associated with gestation, is seen primarily in zebu cows where, in extreme cases, resulted in a total prolapse of the vagina, which included exteriorization of the cervix. Given the high commercial value of elite animals presenting this condition, the increase in cases observed led to attempts to solve the condition with conventional techniques such as those of Caslick, Bühner and Flessa. However, reoccurrence of the prolapse was commonly observed soon after the use of these techniques. Considering these difficulties, the aim of the present work was to develop two new surgical techniques employed in the correction of vaginal prolapse, named partial vaginectomy and dorsal vaginopexy in cows. The research was conducted in the field, using 812 zebu cows of reproductive age, maintained in several properties in different Brazilian states. The animals selected had the vaginal alteration while maintaining all clinical parameters of heart rate, respiratory rate and body temperature, all within normal range. The diagnosis of a vaginal prolapse was performed by anamnesis and analysis of the clinical signs, such as visualization of the vagina through the vulva, tenesmus, agitation, lesions in the everted portin and vaginitis. Evaluation of the animals allowed for the definition of stages of the disease, aiding the choice of an adequate surgical technique. Anesthetic protocols were performed taking into consideration the selected surgery. Partial vaginectomy was employed for the treatment of vaginal prolapses of grade 1, whereas dorsal vaginopexy was used for the grade 2 and 3 prolapses. Post-surgical results for both techniques indicated a high percentage of recovery... (Complete abstract click electronic access below)

Made available in DSpace on 2015-06-17T19:33:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-30. Added 1 bitstream(s) on 2015-06-18T12:48:06Z : No. of bitstreams: 1 000830410_20160705.pdf: 100454 bytes, checksum: b6479857f15ccefd29d8a0db890b3088 (MD5) Bitstreams deleted on 2016-07-25T13:17:38Z: 000830410_20160705.pdf,. Added 1 bitstream(s) on 2016-07-25T13:18:45Z : No. of bitstreams: 1 000830410.pdf: 313399 bytes, checksum: c909ef35b6c646b1a182b7e42b3dea50 (MD5) / Este trabalho teve como objetivo padronizar e avaliar a técnica dot blotting para o diagnóstico sorológico da brucelose bovina, comparar os resultados com os encontrados nos testes de antígeno acidificado tamponado (AAT), 2-mercaptoetanol (2-ME) e fixação de complemento (RFC), além de estimar a sensibilidade e a especificidade relativa do dot blotting em comparação com os testes de diagnóstico oficiais. Para tanto, utilizaram-se 50 amostras de soro sanguíneo bovino para padronização do teste, e foram avaliados dois antígenos: Brucella abortus B19 obtida a partir da vacina ANABORTINA® B19 - Merial, após processo de ruptura do microrganismo, e extrato polissacarídico obtido de amostra de Brucella abortus S99 pelo método água quente - fenol quente. Ao final da padronização foi estabelecida como ideal para a técnica a utilização de membrana de nitrocelulose no formato de círculo, o antígeno obtido da Brucella abortus após passar por um processo de ruptura do microrganismo, como suporte a placa de cultivo celular de 24 poços e fundo chato, a diluição do soro de 1:100 e do conjugado de 1:30.000, além de 3 lavagens por etapa. A avaliação e a comparação da sensibilidade e especificidade relativa aos testes de AAT, 2-ME e RFC foram feitas utilizando 1.315 amostras, sendo estes resultados comparados por meio do indicador Kappa. A comparação dos resultados do dot blotting com o AAT mostrou índice Kappa de 0,9081 (IC95%: 0,8542 - 0,9621), sensibilidade 88% (IC95%: 83,75% - 92,25%) e especificidade 99,45% (IC95%: 98,8% - 99,75%); com o 2-ME, índice Kappa de 0,9939 (IC95%: 0,939 - 1,0484), sensibilidade 99,48% (IC95%: 97,11% - 99,91%) e especificidade 99,91% (IC95%: 99,49% - 99,989%); com a RFC, índice Kappa de 0,8226 (IC95%: 0,7690 - 0,8761), sensibilidade 100% (IC95%: 97,42% - 100,0%) e especificidade 95,40% (IC95%: 94,03% - 96,47%). Usando a combinação dos resultados do 2-ME e da RFC para ... / This study aimed to standardize and evaluate the dot blotting technique for the serologic diagnosis of bovine brucellosis, compare the results with those found in the Bengal test (AAT), 2-mercaptoethanol (2-ME) and complement fixation (CF) and also estimate the relative sensitivity and specificity of dot blotting in comparison with the official diagnostic tests. In order to do this, 50 samples of bovine blood serum were used for test standardization, and two antigens were evaluated: Brucella abortus B19 bacteria obtained from ANABORTINA® B19 vaccine - Merial, after the rupture process of the microorganism, and a polysaccharide extract obtained from a sample of Brucella abortus S99 by the hot water method - hot phenol. At the end of standardization, the use of nitrocellulose membrane in a circle format was established as ideal for the technique, the antigen obtained from B. abortus bacteria after going through the rupture process of the microorganism, as a support a cell culture plate with 24 flat bottom wells was used, a dilution serum of 1:100 and the conjugate of 1:30,000, and washing 3 times per step. The evaluation and comparison of relative sensitivity and specificity with the AAT, 2-ME and CF tests was done using 1,315 samples, and these results were compared using the Kappa indicator. The comparison between the results of dot blotting and the AAT showed a Kappa index of 0.9081 (IC95%: 0.8542 - 0.9621), sensitivity of 88% (IC95%: 83.75% - 92.25%) and specificity of 99.45% (IC95%: 98.8% - 99.75%); 2-ME test, Kappa index of 0.9939 (IC95%: 0.939 - 1.0484), sensitivity of 99.48% (IC95%: 97.11% - 99.91%) and specificity of 99.91% (IC95%: 99.49% - 99.989%); complement fixation test, Kappa index of 0.8226 (IC95%: 0.7690 - 0.8761), sensitivity of 100% (IC95%: 97.42% - 100%) and specificity of 95.40% (IC95%: 94.03% - 96.47%). Using the combination of the results of 2-ME and RFC to establish the true condition of the animal, the ...

Orientador: Teresa Cristina Goulart de Oliveira Sequeira / Banca: Claudio Roberto Madruga / Banca: Márcia Cristina Sena de Oliveira / Banca: Lúcia Helena O'Dwyer / Banca: Agueri Kohayagawa / Resumo: A dinâmica das infecções naturais por Babesia bovis, Babesia bigemina e Anaplasma marginale, foi investigada ao longo do primeiro ano de vida de bezerros da raça Nelore criados em sistema extensivo no Estado de São Paulo, com o propósito de se avaliar a influência da criação exclusiva e extensiva de bovinos da raça Nelore sobre a epidemiologia desses hemoparasitas. Amostras de sangue de 17 animais P.O. foram colhidas a cada 15 dias do nascimento até os quatro meses, e então, a cada 30 dias até um ano. Amostras de sangue colhidas da ponta da orelha foram utilizadas para a confecção de esfregaços sanguíneos, e amostras de sangue da veia jugular foram utilizadas para a determinação da contagem total de eritrócitos (RBC), concentração de hemoglobina (HB), volume globular (VG), contagem total de leucócitos (CTL) e extração de DNA. As teleóginas colhidas foram incubadas em estufa BOD e posteriormente submetidas ao processo de extração de DNA. A amplificação do DNA dos hemoparasitas foi feita pelas técnicas de PCR e nPCR, utilizando-se respectivamente os primers BoF e BoR; BoFN e BoRN para Babesia bovis, BiIA e BilB; BilAN e BilBN para B. bigemina e Am9 e Am10; Am11 e Am12 para A. marginale. Ao longo de um ano de experimento não foram observados casos clínicos de tristeza parasitária, e os quatro animais em que parâmetros hematológicos indicativos de anemia foram detectados concomitantemente com uma ou mais espécies de hemoparasitas se recuperaram sem que houvesse necessidade de tratamento. Babesia bovis não foi detectada nos esfregaços sangüíneos corados por Giemsa, porém merozoítas de B. bigemina foram encontrados em 5 amostras de sangue provenientes de 4 animais. Corpúsculos intraeritrocitários de A. marginale foram detectados em 29 amostras oriundas de 14 animais, nas quais a mais elevada taxa de parasitemia foi de 26%... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The dynamics of natural Babesia bovis, Babesia bigemina and Anaplasma marginale infection was investigated along the first year of Nelore calves, raised on extensive system in São Paulo State. The purpose was to evaluate the influence of the exclusive and extensive breeding of Nelore bovine on the epidemiology of those hemoparasites. Blood samples of 17 purebred animals were harvested every 15 days beginning on the first day of birth till four months old, and then, every 30 days till one year old. Blood samples from the ear tip were used to made blood smears, and blood samples were taken from the jugular vein to determine the red blood cells total count (RBC), hemoglobin concentration (HB), haematocrite (VG), leukocytes total count (LTC) and DNA extraction. The engorged Boophilus microplus were incubated and submitted to the DNA extraction process. The hemoparasite DNA amplification was made by PCR and nPCR respectively, using the primers BoF and BoR; BoFN and BoRN for Babesia bovis, BiIA and BilB; BilAN and BilBN for B. bigemina and Am9 and Am10; Am11 and Am12 for A. marginale. Clinical cases of parasitic sickness were not observed along one year of experiment. The four animals that were observed with indication of anemia hematological parameters, detected at the same time with one or more hemoparasites species, recovered without treatment. Babesia bovis was not detected in the blood smears. However, B. bigemina merozoites were found in five blood samples coming from four animals. A. marginale was detected in 29 blood samples of 14 animals, in which the highest parasitemia level was 26%. The reactions of PCR and nPCR revealed the presence of B. bovis DNA in seven blood samples (four by PCR) from three animals, one of them born in less than 24 hours... (Complete abstract, access undermentioned electronic address) / Doutor

No description available.

In South Africa, trypanosomosis also known as Nagana, transmitted by Glossina brevipalpis and G. austeni, is the major cause of anaemia and chronic debilitating condition in cattle. There is a wealth of entomological information on the ecology of the two tsetse species generated following the devastating outbreak in cattle due to Nagana in 1990. However, it is unfortunate that these entomological data has not been supported by parallel studies on the epidemiology of the disease. Therefore, the present study presents the first intensive epidemiological investigations since 1990 to address the problem of animal trypanosomosis in South Africa. The relationship between trypanosomes herd average prevalence (HAP), herd average anaemia (HAA) and herd average packed cell volume (HA-PVC) were investigated in cattle in three communal diptanks located by the Hluhluwe-uMfolozi Game Reserve by regular monthly sampling for 15 months. The tsetse challenge with G. brevipalpis in two of the diptanks, Mvutshini and Ekuphindisweni, was high but low in the third (Ocilwane). In addition, G. brevipaplis and G. austeni coexist in Mvutshini diptank. This high and low tsetse challenge presented different disease scenarios. Cattle at Mvutshini and Ekuphindisweni diptanks had the highest HAP of 12.3% and 8.9%, respectively, which is significantly different (p = 0.001) from the HAP obtained from cattle at Ocilane (2.9%). Both cattle herds at Mvutshini and Ekuphindisweni diptanks also had the highest HAA, 27.7 and 33.4%, respectively, while cattle at Ocilwane had the lowest, 11.1% (statistically different; p = 0.001). Conversely, cattle at Ocilwane diptank had the highest HA-PCV, ranging between 29-32% while cattle at Mvutshini and Ekuphindisweni diptanks had the lowest HA-PCV (24-29%). The interaction between HAP and HAA is significant (p = 0.021). The overall effect of HAP on the animal health condition is clearly demonstrated when comparing the anaemia in trypanosomes infected and uninfected cattle at the 3 diptanks. Fifty percent, 63% and 100% of trypanosomes infected cattle were anaemic at Mvutshini, Ekuphindisweni and Ocilwane diptanks, respectively. In comparison, the prevalence of anaemia in uninfected cattle in the 3 diptanks was 20, 30 and 10% at Mvutshini, Ekuphindisweni and Ocilwane diptanks, respectively. By combining the data from the 3 diptanks (1,800 observations), the overall HAA in infected and uninfected cattle was 62 and 20%, respectively The results of trypanosomes seasonal surveys conducted at 7 communal diptanks in tsetse infested areas, showed that all cattle at the diptanks were infected with trypanosomes with mean HAP and HAA of 10.3 and 35.3%, respectively. The highest HAP (range 15-31%, n=4) was recorded in Ngwenyambili diptank. This high infection in the cattle herds produced high values of HAA (50%; range 40-60). The infection rate with trypanosomes in G. brevipalpis caught from the field showed immature infections in the midgut of 3.5% (16/458) while only one fly was found with mature infection in the proboscis (1/458, 0.22%). Very few G. austeni were collected (total of 9) during the same period and dissected. The infection rate with trypanosomes immature and mature infections was found to be very high; 5/9 (55.5%). Blood samples were collected from a total of 132 buffaloes randomly immobilized for tuberculosis testing by the Hluhluwe-uMfolozi Game Reserve Authority. Two buffaloes were found to have T. congolense infection by the buffy coat technique. The presence of trypanosomes infected buffaloes in this study confirms the occurrence of sylvatic cycle at the tsetse/livestock/Hluhluwe-uMfolozi Game Reserve, thus, presenting a high risk of serious disease to cattle. The objective of the study on the strategic treatment of trypanosomosis conducted on one farm in endemic area was to treat adult cows and calves at an arbitrary HAP threshold before the disease produces any clinical symptoms or production losses. The strategic use of ethidium bromide and novidium chloride produced attractive results whereby cattle were protected for an extended period of 3 to 6 months with no development of anaemia during this period. Therefore, two to four treatments per year may be sufficient to keep cattle productivity on the farm under the tsetse challenge Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Veterinary Tropical Diseases / unrestricted

Lumpy skin disease (LSD) is an economically important and debilitating disease of cattle caused by the lumpy skin disease virus (LSDV), a poxvirus in the genus Capripoxvirus. The disease is of economic importance to farmers in endemic regions and is a major constraint to international trade in livestock and their products. It is characterised by fever, enlargement of superficial lymph nodes, loss of weight, inappetence, salivation, lachrymation and formation of eruptive circumscribed skin lesions. The quality of meat and milk are reduced; there is infertility due to reduced sperm quality, abortions and reduced calving rates. The hides are permanently scarred, thereby reducing their quality and trade may be affected following movement restrictions from affected areas. v Lumpy skin disease has the potential to become an emerging disease because of global climate change and changes in patterns of trade in animals and animal products. The disease has become endemic in Africa except in countries like Libya, Algeria, Tunisia and Morocco, where the disease has never been reported. It has also spread to the Middle East where outbreaks were first reported in Israel (1989), Kuwait (1991), Saudi Arabia (1990) , Lebanon (1993), The United Arab Emirates (2000) and Oman (2010). In endemic areas, LSD outbreaks are common in summer. The persistence of LSDV between inter-epidemic periods has not been determined and there is no carrier state reported in either cattle or wild animals. Transmission of the disease has been associated with a high incidence of biting insects such as in wet conditions. The spread of LSD from Egypt to Israel e.g. was associated with movement of the stable fly, Stomoxys calcitrans. The virus has been recovered from S. calcitrans and Biomya fasciata, caught while feeding on infected animals and transmission by insects is suspected to be mechanical, which has been demonstrated in Aedes aegypti mosquitoes. During the 1957 outbreak of LSD in Kenya, affected animals were observed to have high tick infestations, especially of Amblyomma species. In a pilot trial in 2008 at the University of Pretoria (UP), Department of Veterinary Tropical Diseases (DVTD), Amblyomma hebraeum, Rhipicephalus appendiculatus and R. (B) decoloratus ticks were implicated in the transmission of LSDV. The overall objective of this study was to investigate the vector competence of three common sub-Saharan tick species (R. (B) decoloratus, R. appendiculatus and A. hebraeum) and their potential roles in the epidemiology of LSD. This was achieved by testing for persistence of LSDV in ticks and its subsequent transmission to recipient animals following interrupted feeding, transstadial and transovarial development of the ticks. The over-wintering of LSDV was also investigated during transstadial passage in A. hebraeum and transovarial passage in R. (B) decoloratus. During the study, seven cattle were artificially infected with LSDV to serve as source (donors) of infection to ticks. To test for mechanical / intrastadial transmission and persistence in ticks, adult ticks (A. hebraeum and R. appendiculatus) were partially fed on donor animals and then transferred to recipient animals or collected for testing. To test for transstadial transmission/passage, nymphal stages of A. hebraeum and R. appendiculatus were fed on donor animals until they engorged and dropped. Engorged nymphs were incubated to moult to adults. The emergent adults were placed on recipient animals and also tested for the virus. To test for transovarial transmission and passage R. (B) decoloratus (one- host tick) larvae were fed on donor animals until engorged adults. For R. appendiculatus and A. hebraeum (three-host ticks), adults were fed to repletion on the donor animals. Engorged females were collected and incubated to lay eggs and the eggs were allowed to hatch. The emergent larvae were placed to feed on recipient animals to test for transovarial transmission, while larvae were tested for the presence of the virus. Over-wintering of LSDV in ticks was tested by transstadial passage in A. hebraeum and transovarial passage in R. (B) decoloratus under fluctuating reduced temperatures, simulating wintery climatic conditions. Engorged A. hebraeum nymphs and R. (B) decoloratus females were infected by intracoelomic injection. The presence of the virus in LSDV- infected animals was tested by real-time PCR, virus isolation (VI), and the serum neutralisation test (SNT). Tick saliva was tested by real-time PCR and VI while ticks were tested by immunohistochemistry, transmission electron microscopy, VI and real-time PCR. Mechanical/intrastadial and transstadial transmission is reported in A. hebraeum and R. appendiculatus. Transovarial transmission was reported in A. hebraeum, R. appendiculatus and R. (B) decoloratus. The virus was demonstrated in saliva and tick organs of A. hebraeum and R. appendiculatus adults following both mechanical/intrastadial and transstadial persistence. Transovarial passage of LSDV was demonstrated in R. (B) decoloratus, R. appendiculatus and A. hebraeum larvae. The virus also persisted through cold temperature exposure during transstadial passage in A. hebraeum and transovarial passage in R. appendiculatus. This study confirms the vector competency of A. hebraeum, R. appendiculatus and R. (B) decoloratus ticks for LSDV. It also shows the potential for LSDV to over-winter in ticks and demonstrates that LSDV may persist in ticks during inter-epidemic periods. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Veterinary Tropical Diseases / unrestricted