Veterinary extension on sampling techniques related to heartwater research.

Heartwater, a tick-borne disease caused by Ehrlichia ruminantium, is considered to be a significant cause of mortality amongst domestic and wild ruminants in South Africa. The main vector is Amblyomma hebraeum and although previous epidemiological studies have outlined endemic areas based on mortalities, these have been limited by diagnostic methods which relied mainly on positive brain smears. The indirect fluorescent antibody test (IFA) has a low specificity for heartwater organisms as it cross-reacts with some other species. Since the advent of biotechnology and genomics, molecular epidemiology has evolved using the methodology of traditional epidemiology coupled with the new molecular techniques. A new quantitative real-time polymerase chain reaction (qPCR) test has been developed for rapid and accurate diagnosis of heartwater in the live animal. This method can also be used to survey populations of A. hebraeum ticks for heartwater. Sampling whole blood and ticks for this qPCR differs from routine serum sampling, which is used for many serological tests. Veterinary field staff, particularly animal health technicians, are involved in surveillance and monitoring of controlled and other diseases of animals in South Africa. However, it was found that the sampling of whole blood was not done correctly, probably because it is a new sampling technique specific for new technology, where the heartwater organism is much more labile than the serum antibodies required for other tests. This qPCR technique is highly sensitive and can diagnose heartwater in the living animal within 2 hours, in time to treat it. Poor sampling techniques that decrease the sensitivity of the test will, however, result in a false negative diagnosis. This paper describes the development of a skills training programme for para-veterinary field staff, to facilitate research into the molecular epidemiology of heartwater in ruminants and eliminate any sampling bias due to collection errors. Humane handling techniques were also included in the training, in line with the current focus on improved livestock welfare.

Case-control study to determine whether river water can spread tetracycline resistance to unexposed impala (Aepyceros melampus) in Kruger National Park (South Africa).

A case-control study was performed in the Kruger National Park (KNP), South Africa, to find out whether impala (Aepyceros melampus) were more likely to harbor tetracycline-resistant Escherichia coli (TREC) in their feces when they drank from rivers that contained these bacteria than when they drank from rivers that were uncontaminated with TREC. The following five perennial rivers were selected: the Crocodile, the Letaba, the Olifants, the Sabie, and the Sand. Samples of river water (n = 33) and feces (n = 209), collected at 11 different sites, were cultured for E. coli. The resulting colonies were screened for tetracycline resistance by use of the Lederberg replica plating method (breakpoint, 4 mg/liter). A resistant and/or a susceptible isolate was then selected from each sample and subjected to the CLSI MIC broth microdilution test for tetracyclines. Among the 21 water specimens contaminated by E. coli, 19.05% (n = 4) were found to be resistant by the MIC method (breakpoint, >/=8 mg/liter). This led to the Crocodile, Olifants, and Letaba rivers being classified as TREC positive. Among the 209 impala feces sampled, 191 were positive for the presence of E. coli (91.38%). Within these (n = 191), 9.95% (n = 19) of the isolates were shown to be TREC by the MIC method. It was found that 1.11% (n = 1) of the E. coli isolates cultured from the feces of the control group (n = 90) were TREC, in comparison with 17.82% (n = 18) of those in feces from the exposed group (n = 101). The calculation of the odds ratio showed that impala drinking from TREC-contaminated rivers were 19.3 (2.63 to 141.69) times more likely to be infected with TREC than were unexposed impala. This is a significant finding, indicating that surface water could be a possible source of antimicrobial resistance in naïve animal populations and that impala could act as sentinels for antimicrobial resistance.

An investigation of the quality of meat sold in Lesotho.

Since the closure of the Lesotho abattoir in 2003, only imported meat can be legally sold. However, it was estimated in 2007 that 80% of the meat sold at butcheries comes from informal slaughter. The aim of this study was to investigate the situation. The number and location of informal butcheries in Lesotho (n = 143) were recorded and mapped using Geographical Information Systems. Observations (photographs) of informal slaughter indicated a lack of hygiene, unskilled slaughtermen and illegal disposal of offal with possible environmental pollution. In addition, a cross-sectional study was undertaken to determine the microbiological quality of meat from randomly selected carcasses (n = 237) of cattle, sheep and pigs from a sample of 44 butcheries, 4 of which were associated with registered supermarkets. As a control, samples for microbiological assay were taken from imported meat originating from carcasses (n = 20) slaughtered at a registered abattoir in South Africa. Of the 44 butcheries investigated only the 4 commercial butcheries associated with supermarkets sold imported meat only; 3 butcheries sold meat inspected at government slaughter slabs (n = 3), while the rest (n = 37) sold both imported and informally slaughtered meat. In terms of Lesotho legislation, informally slaughtered meat is only for home consumption. The bacteriological counts from all samples showed a total bacterial plate count exceeding 30 organisms per ml in contrast with the controls which all showed a count less than 5 colonies per ml. This was found for both imported and informally slaughtered meat sold in Lesotho. In addition, meat samples from butcheries showed the presence of the potential pathogens Salmonella (n = 2), Staphylococcus aureus (n = 12) and Escherichia coli (n = 15). During the study, anthrax was confirmed in 9 human patients, 5 of whom died, after consumption of informally slaughtered livestock. Although no cases of animal abuse were detected, it was considered that informal slaughter can prejudice livestock welfare. It was concluded that the current situation is not acceptable in terms of meat safety. Thus, the Veterinary Public Health Directorate of the National Veterinary Services has prioritised the monitoring of butchers, registration of slaughter slabs and a general extension campaign to improve hygiene and animal welfare standards for slaughter in Lesotho. This paper highlights the major risks associated with meat consumption without Veterinary Public Health intervention in accordance with international standards.

A quantitative real-time PCR assay for Ehrlichia ruminantium using pCS20.

Heartwater is a tick borne disease that affects ruminants and wild animals in Africa south of the Sahara. It is caused by Ehrlichia ruminantium and transmitted by the tick Amblyomma hebraeum. The protocols currently used to detect heartwater take several days to complete. Here, we describe the development of a pCS20 quantitative real-time PCR TaqMan probe assay to detect E. ruminantium in livestock blood and ticks from the field. The assay is based on the conserved pCS20 gene region of E. ruminantium that contains two overlapping genes, rnc and ctaG [Collins, N.E., Liebenberg, J., De Villiers, E.P., Brayton, K.A., Louw, E., Pretorius, A., Faber, F.E., Van Heerden, H., Josemans, A., Van Kleef, M., Steyn, H.C., Van Strijp, M.F., Zweygarth, E., Jongejan, F., Maillard, J.C., Berthier, D., Botha, M., Joubert, F., Corton, C.H., Thomson, N.R., Allsopp, M.T., Allsopp, B.A., 2005. The genome of the heartwater agent Ehrlichia ruminantium contains multiple tandem repeats of actively variable copy number. PNAS 102, 838-843]. The pCS20 quantitative real-time PCR TaqMan probe was compared to the currently used pCS20 PCR and PCR/32P-probe test with regards to sensitivity, specificity and the ability to detect DNA in field samples and in blood from experimentally infected sheep. This investigation showed that the pCS20 quantitative real-time PCR TaqMan probe was the most sensitive assay detecting seven copies of DNA/mul of cell culture. All three assays, however, cross react with Ehrlichia canis and Ehrlichia chaffeensis. The pCS20 real-time PCR detected significantly more positive field samples. Both the PCR and pCS20 real-time PCR could only detect E. ruminantium parasites in the blood of experimentally infected sheep during the febrile reaction. The PCR/32P-probe assay, however, detected the parasite DNA 1 day before and during the febrile reaction. Thus, because this new quantitative pCS20 real-time PCR TaqMan probe assay was the most sensitive and can be performed within 2h it is an effective assay for epidemiological surveillance and monitoring of infected animals.

Seroprevalence of toxoplasmosis in sheep in South Africa.

Serum samples from 600 sheep were collected from 5 different provinces randomly chosen in South Africa. Two sheep abattoirs (representing formal slaughter of sheep) and 1 rural location (representing informal slaughter of sheep) per province were also selected randomly. The serum samples were tested for anti-Toxoplasma gondii IgG antibodies using 2 different serological tests: an indirect fluorescent antibody (IFA) test and an enzyme-linked immunosorbent assay (ELISA) test available as a commercial kit. This study provides the first published data on seroprevalence of toxoplasmosis in sheep in South Africa, although positive titres have been found previously in wild felids, ferrets, chinchillas and a dog. Data on seroprevalence in sheep is considered important because consumption of mutton is universally considered to be a source of zoonotic transfer to humans. Seroprevalence in humans in South Africa was previously found to be 20 % and it is postulated that this may be linked to the informal slaughter and consumption of mutton. During this study, the overall national seroprevalence per province in sheep was found to be 5.6 % (IFA) and 4.3 % (ELISA), respectively. This is lower than in other countries, possibly because South Africa has an arid climate. Differences in seroprevalence in different areas studied suggested an association with the climate and a significant correlation (P > 0.05) was detected between the prevalence of T. gondii and the minimum average temperature. The seroprevalence was found to be significantly higher (P < 0.01) in sheep originating from commercial farms (7.9 %) than in rural sheep in the informal sector (3.4 %). Also, sheep managed extensively had a seroprevalence of 1.8 %, which was significantly lower (P < 0.05) than the seroprevalence in sheep under semi-intensive or intensive management systems (5.3%). An incidental finding of interest was the considerable movement of sheep to abattoirs and mutton after slaughter. The highest consumption of mutton was in the Western Cape Province (29.9%) while the highest concentration of sheep is found in the Eastern Cape Province (30.1%).

Evaluation of the application of a thermostable Newcastle disease vaccine by community volunteers in the North West Province of South Africa.

Participatory research on vaccination of village poultry against Newcastle disease (ND) was carried out in the village of Disaneng, in the North West Province of South Africa. Three application methods for ND Inkukhu vaccine were shown to induce sufficient levels of immunity in back-yard poultry when correctly administered. These are eye-droplet administration to individual fowls, in-feed and in-water administration to small flocks. After a community meeting and group discussion to select methods of vaccination, only 2 of the 3 methods were chosen; the individual administration of droplets into the eyes was considered to be too impractical because back-yard fowls are difficult to catch. Visual and practical training material was prepared and presented to volunteer vaccinators (n = 23). Vaccinators were then required to register all the poultry owners in their ward who wished to have poultry vaccinated. Once an indication of the number of chickens to be vaccinated had been made available, ND Nobilis Inkukhu vaccine was supplied to vaccinators free of charge. Community vaccinators were responsible for the organisation of the vaccination campaign, including storage and preparation of vaccine for application. All 9 wards in the village were initially involved with a total of 482 households, owning 6141 chickens, participating. This represented slightly in excess of 60 % of the fowls in the area. Involvement in a 2nd round of vaccinations, 1 month later, was far poorer with only 211 households owning a total of 1636 chickens participating. Serum samples were collected from vaccinated fowls using systematic random sampling and tested for circulating antibodies. The levels of protection varied, with no significant difference found between in-feed and in-water vaccine administration. Volunteer vaccinators were found to be unreliable, easily demotivated, did not keep good records and left the project when offered permanent employment. Contacting them to make arrangements for delivering vaccine was difficult and time consuming. Structured interviews indicated that deaths in poultry and the attitude of the owners probably contributed to the demotivation of the volunteers used as community vaccinators. It was concluded that volunteers are not the ideal choice for vaccination of village poultry against Newcastle disease.

Participatory rural appraisal to investigate constraints in reporting cattle mortalities in the Odi district of North West Province, south Africa.

Mortalities in cattle can have severe financial implications for small scale and communal farmers in South Africa. They could also be a measurable indicator for surveillance of animal diseases, such as those listed by the Office International des Epizooties (OIE), or diseases included in the regulations of the South African Animal Diseases Act, 1984 (Act 35 of 1984). In order to prevent further mortalities and for accurate surveillance and monitoring of diseases, it is important that farmers participate in the determination of causes of mortality in their cattle. This paper reports on constraints of the reporting diseases to the state veterinary services, the study area being Odi district, in the North West Province. The method that was followed was based on participatory rural appraisal. The selected cattle owners participated in every phase. They were the ones who first spoke to veterinary services about ways to decrease the diseases and mortalities of their cattle. A questionnaire to verify the facts complemented the survey. A total number of 60 farmers were randomly selected from 12 villages. One farmer withdrew, leaving 59 farmers. Most of the farmers in the study were men ( n = 55). The area of study was communal and the farming system traditional and extensive. It was suspected that there was a communication problem and this was proven by the results of the research, as 23 farmers were not even aware that mortalities have to be reported by law. The real problem was that causes of death were not being diagnosed because farmers were not aware that a necropsy could give information on the causes of death. Farmers were keen to receive training in elementary necropsy techniques so as to be able to discuss the cause of death of cattle with the state veterinarian.

Use of scanning electron microscopy to confirm the identity of lice infesting communally grazed goat herds.

Lice have been described on goats in commercial farming systems in South Africa but not from flocks on communal grazing. During a longitudinal survey on the causes of goat kid mortality, conducted in Jericho district, North West Province, lice were collected from communally grazed indigenous goats. These lice were prepared for and viewed by scanning electron microscopy, and micro-morphological taxonomic details are described. Three species of lice were found in the study area and identified as Bovicola caprae, Bovicola limbatus and Linognathus africanus. Sucking and biting lice were found in ten of the 12 herds of goats examined. Lice were found on both mature goats and kids. Bovicola caprae and L. africanus were the most common biting and sucking lice respectively in all herds examined. Scanning electron microscopy revealed additional features which aided in the identification of the louse species. Photomicrographs were more accurate aids to identification than the line drawings in the literature and facilitated identification using dissecting microscope.

An economic analysis of communal goat production.

The economic impact of different extension messages used was calculated using enterprise budgeting (gross margin analysis). Input data were gleaned from the literature, from participatory appraisals, as well as a field study, spanning 12 months, of small-scale communal goat farming systems in Jericho in the Odi District of North West Province. The number of offspring weaned per annum, as a proportion of does owned, was selected as the desired output for analysis. This study has shown that small-scale communal goat farmers are not adopting or implementing extension messages to improve production capacity. In South Africa the majority of goats are slaughtered in the informal sector. If the informal sector is to be persuaded to market goats commercially through formal channels, then knowledge of the economics of goat farming on communal lands should be provided. The economic aspects of extension messages are probably an important factor in determining acceptance and sustainability yet appear to be seldom investigated. The probable reason for lack of adoption of standard extension messages, which promote improved nutrition, parasite control, vaccination and treatment of goats, was economic. In other words, the so-called 'poor management practices' used by communal farmers appeared to be economically more profitable than the 'good management practices' suggested to increase production. The price of communal goats was not related to their mass. A higher level of inputs would probably have resulted in a heavier kid, however it was established that this would not have influenced the price received as a majority of the goats were slaughtered for ritual purposes where age, colour and sex were more important to the purchaser than body mass. It is standard practice in commercial farming systems to evaluate the economic benefits of all management practices before they are implemented. Production animal veterinarians use veterinary economics to compare different scenarios to control diseases or select management practices in commercial herds. It is suggested that the inputs and outputs of small-scale farming systems should be carefully analysed and that veterinary economics should also be used to evaluate the probable impact of extension messages formulated by veterinarians and animal health technicians.

An investigation into the causes of low calving percentage in communally grazed cattle in Jericho, North West Province.

The communal grazing system is generally understood to have a low input, low output type of management. However, the actual inputs and outputs of the farmers are not well known and the farmers are often unaware of their problems. Although the causes of low calving percentage are well understood in commercial beef farming enterprises in South Africa, the same is not true for communal farming systems. The aim of this study was to determine the reproductive performance of beef cattle on a communal farming system in Jericho, North West Province. Ten farmers from five villages with a total of 265 cows and 13 bulls were purposively selected. The selection criteria were that each farmer had to have a minimum of 10 breeding cows and a bull and be willing to participate in the study. This was followed by a 12-month longitudinal study with monthly herd visits where cows were examined rectally and bulls (n = 13) were subjected to a single breeding soundness evaluation. The calving percentage was found to be 37.7%. This is lower than the recorded percentages for commercial beef cattle on extensive grazing. The factors playing a role in low calving percentage were ranked using field data. From this it appeared that failure of cows to become pregnant was the main cause of poor calving percentage as opposed of loss of calves through abortion or resorption. Sub-fertility of the bulls was found to be of great significance and it is proposed that this be included in extension messages and that bulls be fertility tested routinely. Poor body condition score of cows, mainly caused by poor management, was also considered to play a major role in reducing pregnancy rates. Infectious diseases like trichomonosis, campylobacteriosis and brucellosis played a much leser role than anticipated.

The use of dried bakery products in a free-choice feeding method for small-scale broiler production.

Waste material from bakeries is an unconventional energy feed source which is available in sufficient quantities for use in small-scale broiler production in South Africa. Small-scale broiler producers do not have access to the computer programs required to balance home-mixed rations. This investigation confirms that the use of dried bakery products (DBP) in a 2-stage, free-choice method can be used to compensate for this lack. A total of 570 day-old male broiler chickens was assigned to 3 feeding treatments: the control group was fed a 2-stage feeding programme using standard commercial starter and grower rations. The 2nd group received a commercial starter ration up to Day 7 and was thereafter given a choice of a commercial starter ration with normal salt content (0.35%) and DBP. The 3rd group was fed a commercial starter ration up to Day 7, then offered a choice of commercial starter ration with a lower salt content (0.1%) and DBP. The low salt alternative was used to test whether the higher salt percentage in DBP influenced the choice of feed by the birds. It was found that the control group consumed significantly more feed (P < 0.05) and was significantly heavier (P < 0.05) than the experimental groups. However, there was no significant difference between the 2 experimental groups, which indicated that salt content did not play a role in the choice of ration. Feed consumption by both experimental groups was about one-third less than the control group, but the profit margin, as calculated using gross margin analysis, was approximately 15 % higher. It was therefore concluded that dried bakery products can be profitably incorporated as an energy feed source, using the free-choice feeding method, in small-scale broiler enterprises.

Mathematics at matriculation level as an indicator of success or failure in the 1st year of the Veterinary Nursing Diploma at the Faculty of Veterinary Science, University of Pretoria.

Mathematics at matriculation level (Grade 12) is one of the subjects required for admission to the Veterinary Nursing Diploma in the Faculty at Veterinary Science of the University of Pretoria. The present study shows that there is no statistically significant relationship between the grade of mathematics at matriculation level and the success or failure in the 1st year of study. There is, however, a statistical difference in the adjusted mark obtained for mathematics at matriculation level between the groups that passed and failed the 1st year of the veterinary nursing course. The results of this research are not consistent with other research which showed that secondary school mathematics results are not a significant factor in tertiary education. It is recommended that selection criteria for veterinary nurses should in future still include mathematics, but that cognisance should be taken of the mark obtained and students with higher marks (above 57%) given preference.