Mechanisms by which lumpy skin disease virus is shed in semen of artificially infected bulls

Lumpy skin disease (LSD) is a disease of significant economic importance in Africa. It causes considerable production losses and its presence in semen is a constraint to international trade. Recent findings that LSDV viral DNA can be found in the semen of artificially infected bulls for up to five months, while viable virus could be isolated 42 days after infection, indicated the need for studies into the mechanism by which this protracted shedding occurs. Six healthy, seronegative, postpubertal Dexter bulls were housed in vector-free stables and challenged with LSD virus by intravenous injection. Sheath washes, vesicular fluid and semen collection was performed every other day and subjected to PCR. On these days, blood was collected for serum neutralization tests and virus isolation, and ultrasonography of the reproductive tracts performed. Semen was centrifuged to separate cell-rich and seminal plasma fractions, and tested by PCR. Clinical parameters were recorded twice daily. Bulls shedding viral DNA 28 days after challenge were slaughtered, their reproductive tracts were harvested and diagnostic post mortem was performed. Histopathology, immunoperoxidase staining, electron microscopy, virus isolation and PCR were done on tissue samples. Of the six bulls, two showed no clinical signs, two showed mild and two showed severe clinical signs. Fever appeared five to seven days and lesions eight to ten days post challenge. Bulls were viraemic and febrile during the same time. Viral DNA was detected in all semen fractions of all bulls, but mostly from the cell-rich fraction and from the bulls showing the most severe clinical signs. Ultrasonography showed infarction in the testes and epididymides of the two bulls that were most severely affected. Necropsy of the two bulls that were still shedding after 28 days showed testicular degeneration and infarction, as well as epididymal granuloma formation. None of the accessory sex organs showed significant pathology. Histopathological changes seen were necrogranulomata in testes and peididymides. IMP staining of reproductive tissues showed that staining was restricted to areas in the testes and epididymides that were associated with necrosis. Virus could be seen on negative staining EM of sections of the testes. Our results show that LSDV is not limited to specific fractions of the ejaculate and that the testes and epididymides are most profoundly affected. Blood contamination is not responsible for the presence of viral DNA in semen, and it is unlikely that the virus is sperm-associated. Results suggest that the ejaculate is contaminated with viral DNA as it is shed from necrotic lesions in the genital tract. Further research is indicated into the ability of infected semen to produce disease as well as treatment protocols that could render semen free of viral DNA.Dissertation (MMedVet (Theriogenology))--University of Pretoria, 2006.Production Animal Studiesunrestricte

Educational value of group learning activities in MBA education : student perceptions and instructor intentions

The objectives of this study were to assess the perceptions of educational value of group learning held by students and compare it with the intentions of lecturers involved in the MBA programme. Eighty-two MBA students enrolled at the Gordon Institute of Business Science (GIBS) of the University of Pretoria completed an online questionnaire, the results of which reflected an overall positive perception of educational value of group learning. However, negative perceptions of group dynamics, fairness and administrative processes also surfaced. There appears to be some evidence of racial undertones to the negative perceptions. These perceptions were significantly different between junior and senior students. Semi-structured interviews with lecturers and administrative staff revealed markedly different intentions and approaches to group learning. An awareness of the difficulties faced by students in group activities could be demonstrated, but different opinions were held on appropriate interventions. The study concludes with suggestions to improve identified weaknesses through a more focused educational approach. Such an approach would place greater emphasis on personal reflection and addressing of dysfunctional behaviour in groups, as part of a posited central skill in management.CopyrightDissertation (MBA)--University of Pretoria, 2012.Gordon Institute of Business Science (GIBS)unrestricte

Curricular renewal at the southern tip of Africa : the ‘2016’ veterinary curriculum at the University of Pretoria

Four years after the institution of a new curriculum at the University of Pretoria's Faculty of Veterinary Science, a second major curricular renewal was initiated as a result of several pressing drivers, many of which were unique to the national and institutional context. During the project, South African higher education was disrupted by student protests prompted by financial pressures on students, the overt colonial structure of higher education, and the need to accelerate transformation of the sector. A structured curricular renewal process was followed, including the laying down of the principles, the structuring the macro-curriculum as a story, the design of a meso- and micro-curriculum, and the mapping of the curriculum to Day One outcomes. The resulting program is a 6-year bachelor's degree with a blend of discipline and species modules, with the first cohort graduating in 2016. There is a strong focus on skills embodied in a 62-week experiential component, managed using a unique custom-designed online platform for booking placements, documenting exposure, assessing competency, and providing feedback to students. The experiential training includes a large elective component. Several causes of loss of impetus during the process are discussed and proposals are made for avoiding these. The value of accreditation as a driver and a source of inputs is evident. The process has succeeded in producing a significantly reshaped curriculum that has been well received by external stakeholders.http://jvme.utpjournals.press/loi/jvme2018-09-06hj2017Production Animal Studie

Seminal transmission of lumpy skin disease virus in heifers

It is known that lumpy skin disease virus (LSDV) can be shed in bull semen following infection and that artificial insemination (AI) poses a biosecurity risk. It is however not known whether the use of LSDV infected semen in AI poses a biosecurity risk. The aims of the current study were to investigate whether LSDV, transmitted through semen, can infect cows and embryos.. Two controlled trials were performed simultaneously. Eleven (11) young beef heifers, naïve to LSDV, were synchronized using an OvSynch protocol and inseminated with fresh semen spiked with a field strain of LSDV on day 0. Six (6) of the heifers were superovulated on Day 1 using PMSG, and embryos were flushed from these heifers on Day 6. Blood and serum samples were collected from Day 4 until Day 27 to determine the presence of LSDV by PCR and virus isolation, and the presence of antibodies against LSDV by SNT. The first clinical signs of LSD were noticed on Day 10, followed by severe generalized LSD in 3 heifers, and mild LSD in 2 more heifers. Two heifers were humanely euthanized due to severe unresponsive stranguria. LSDV was detected by PCR, virus isolation or electron microscopy in blood, embryos and organs of experimentally infected animals, and 8 heifers had seroconverted by Day 27. Two control animals were not affected. This is the first report of experimental seminal transmission of LSDV in cattle.NRF. Project number FA 200704250000.http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1865-16822015-10-31hb201

Towards ecologically sustainable crop production : a South African perspective

Food production comes at an ecological cost, and the lack of sustainability of South Africa’s crop production systems is becoming increasingly worrisome. While small scale emerging and homestead subsistence farming are significant in the agricultural sector, food production is dominated by large scale commercial agriculture. In this paper we analyse the ecological impact of South African commercial crop production and what can be done about it. Impact categories considered are divided into what we consider ‘better-researched’ problems: fresh water depletion, salinisation, soil degradation, eutrophication and land use change; and into what we consider ‘emerging’ problems for agriculture: greenhouse gas emissions, soil profile acidification, ecotoxicity and non-renewable resource consumption. While there is a paucity of quantitative information, it is clear that after decades of cultivation many of our agroecosystems are degraded or degrading. Sustainable crop production and food security are ‘wicked’ problems – containing dynamic social, economic and biophysical complexities. Increased stakeholder engagement to better understand these problems, the tradeoffs linked to finding solutions and to involve those with the resources to turn knowledge into action is required. Collecting key data, turning it into information within local contexts (involving the ecology, agronomy, sociology, psychology, economics and other disciplines simultaneously) and communicating it effectively to allow learning and adaptive management at various spatial and temporal scales is essential. An example is the display of river flows on a website in real-time to help farmers manage and adapt irrigation practices better, and to connect them with other stakeholders to improve understanding of the responsibilities of managing water at local and catchment scales.The Water Research Commissionhttp://www.elsevier.com/locate/agee2018-01-31hb2017Plant Production and Soil Scienc

The use of electrochemically activated saline as a uterine instillation in pony mares

Twelve pony mares were randomly assigned to either a control or a treatment group and inseminated with fresh, raw semen from a single stallion of known fertility in a cross-over trial design. Pregnancy was diagnosed by transrectal ultrasound 12-14 days post-ovulation and then terminated by administration of a luteolytic dose of cloprostenol. Treatment mares received a uterine instillation of 100 m of electrochemically activated (ECA) saline 4-12 hours post-insemination. Control mares received no treatment post-insemination. Per cycle pregnancy rate was 58.3 % in the control group and 50 % in the treatment group. There was no statistical difference (P = 1.000) in pregnancy rate between the 2 groups. The principles of ECA and applications of ECA saline are discussed

Training method and other factors affecting student accuracy in bovine pregnancy diagnosis

To optimize bovine pregnancy diagnosis (PD) training, factors influencing student performance were investigated. The objective was to determine whether training method, gender, background (farm, urban, or mixed), previous experience in bovine PD, and current career interest influenced the accuracy of bovine PD by trans-rectal palpation (TRP). Fourth-year (of a 6-year program) veterinary students (n=138) received one PD training session in groups using either simulator training on Breed'n Betsy (BB) or training on live cows (C). Students completed a questionnaire on gender, background, and career interest. Students' PD accuracy (pregnancy status and stage) was determined after training when each student palpated six cows with known pregnancy status. Students' accuracy in determining pregnancy status was measured as sensitivity and specificity (the ability to correctly identify the presence and absence of pregnancy respectively). Factors that influenced overall accuracy with a higher student sensitivity of bovine PD by TRP were training method, farming background, an interest in a mixed animal career, and stage of gestation. Gender of students and previous experience in bovine PD did not have an influence. Training on BB simulators was associated with lower student sensitivity for pregnancy detection in cows 6 months pregnant was similar for training on BB simulators and live cows. No evaluated factors were significantly associated with specificity of PD. Teaching efforts focusing on specificity of PD and repeated simulator-based training in conjunction with live cow exposure are recommended.http://jvme.utpjournals.press/loi/jvme2019-11-29hj2018Production Animal Studie

Prevalence of methicillin-resistant Staphylococcus aureus among large commercial pig herds in South Africa

The prevalence of nasal carrier status of methicillin-resistant Staphylococcus aureus (MRSA) in pigs has been described elsewhere, but is unknown in South Africa. To address concerns that exist regarding the zoonotic risk that carriers pose to workers, the herd-level prevalence of MRSA was determined among 25 large (> 500 sows) commercial pig herds in South Africa, representing 45% of the large commercial herds in the country. From each herd, the nasal contents of 18 finisher pigs were sampled at the abattoir, pooled into three and selectively cultured to determine the presence of MRSA. A herd was classified as MRSA-positive if one or more of the three pooled samples cultured positive. Three of the 25 herds tested positive for MRSA, equating to a 12% herd prevalence (95% CI: 7% - 23%) among South African commercial piggeries. The prevalence of nasal MRSA carriers among large commercial pig herds in South Africa was low compared to what has been reported elsewhere and suggests a relatively low zoonotic MRSA risk to workers in South African commercial piggeries and abattoirs.http://www.ojvr.orgProduction Animal Studie

Relationship between production characteristics and breeding potential of 25-month old extensively managed Bonsmara bulls

The aim of the study was to determine if the breeding potential of 25-month old Bonsmara beef bulls could be predicted from production characteristics. Forty-one Bonsmara bulls were included in an on-farm performance test (also known as the Phase D growth test) for a period of 180 days. At an average age of 24.7 months the bulls were subjected to a libido test and overall breeding soundness evaluation (OBE). The bulls were categorised into independent breeding potential categories according to the scores they obtained for the measured reproductive traits. The categories included sperm morphology and motility. One-way ANOVA revealed that none of the production traits measured had a significant effect on the different breeding potential categories. A positive correlation (r = 0.33) was recorded between pre-weaning growth rate and percentage morphologically normal sperm, while a negative correlation (r = -0.36) was recorded between total acrosomal- and flagellar sperm defects and pre-weaning growth. A positive correlation was demonstrated between sperm motility and pre-weaning growth (r = 0.36), and a consequent negative correlation (r = -0.38) between the percentage aberrant sperm movement and pre-weaning growth. The correlation between the percentage morphologically normal sperm and percentage progressively moving sperm was r = 0.50, while the correlation between percentage morphologically normal sperm and aberrant and immotile sperm was r = 0.48 for both variables. The number of total defects correlated highly significantly with flagellar and acrosomal defects (r = 0.72 and r = 0.93, respectively) and correlated poorly with the total number of nuclear defects (r = 0.32). These results suggest that total sperm defects were mainly due to acrosomal and flagellar defects, rather than nuclear defects and as the percentage morphologically normal sperm decreased, the motility also decreased. High growth rates before weaning may have a positive effect, while high growth rates after weaning may have a negative effect on the breeding potential of a bull. None of the measured reproductive and production traits had a significant effect on libido score and thus, cannot be used to predict the libido of young extensively maintained bulls

The effect of Rift Valley fever virus clone 13 vaccine on semen quality in rams

Rift Valley fever (RVF) is an arthropod-borne viral disease of importance in livestock and humans. Epidemics occur periodically in domestic ruminants. People in contact with infected livestock may develop disease that varies from mild flu-like symptoms to fatal viraemia. Livestock vaccination may assist in disease control. Rift Valley fever virus (RVFV) Clone 13 is a relatively new vaccine against RVF, derived from an avirulent natural mutant strain of RVFV, and has been shown to confer protective immunity against experimental infection with RVFV. The hypothesis tested in the current trial was that rams vaccinated with RVFV Clone 13 vaccine would not experience a reduction in semen quality (measured by evaluating the percentage progressively motile and percentage morphologically normal spermatozoa in successive ejaculates) relative to unvaccinated control animals. Ram lambs were screened for antibodies to RVFV using a serum neutralisation test. Animals without detectable antibodies (n = 23) were randomly allocated to either a test group (n = 12) or a control group (n = 11). Animals in the test group were vaccinated with RVFV Clone 13 vaccine. Daily rectal temperature measurements and weekly semen and blood samples were taken from all animals. Seven animals were eliminated from the statistical analysis because of potential confounding factors. Logistic regression analysis was performed on data gathered from the remaining animals to determine whether an association existed between animal group, rectal temperature and semen quality parameters. No correlation existed between the treatment group and values obtained for the semen quality parameters measured. There was no statistically significant post-vaccination decline in the percentage of live morphologically normal spermatozoa, or the percentage of progressively motile spermatozoa, either when assessed amongst all animals or when assessed within individual groups. A repeat study with a larger sample size and a more comprehensive pre-screening process may be indicated to avoid the inclusion of unsuitable animals.The research was conducted as part of a Master’s degree in Veterinary Medicine (Gynaecology) dissertation by G.B. (University of Pretoria). (http://hdl.handle.net/2263/46103)Onderstepoort Biological Productshttp://www.ojvr.orghttp://hdl.handle.net/2263/46103am201