The reported incidence of human campylobacteriosis has markedly increased in developed countries within the last 20 years. The prevalence and importance of Campylobacter spp. as the cause of human gastroenteritis in developing countries is not known, as information is limited due to a lack of national surveillance programmes in these countries. However, it seems likely that the rate of campylobacteriosis is high among infants and children below 2 years of age resulting in substantial morbidity and, to a lesser extent, mortality. The aim of this study was to determine the extent of contamination and cross-contamination of poultry products with Campylobacter in a high-throughput South African chicken processing plant. It is the first research project for the evaluation of the zoonotic risk of Campylobacter for consumers in South Africa. While conventional culture-based detection methods of Campylobacter spp. usually need 4-6 days to produce a result, the polymerase chain reaction (PCR) method developed for this research project took less than 32 hours. Both strains, C. jejuni and C. coli, are the subject of this paper and will be collectively referred to as Campylobacter unless otherwise stated. During the winter of 2004, 300 samples were randomly taken from 50 chicken carcasses directly after evisceration, as well as 25 samples from ready-to-sell packages of fresh intestines (mala) and livers. The samples were taken in batches over a time period of 4 weeks. All samples were examined by means of DNA extraction and PCR resulting in the following findings: The average contamination rates with Campylobacter for both the skin samples and livers were 24%, and for intestines a contamination rate of 28% was found. These results are in line with the findings of other authors. Chicken and chicken products, especially livers and intestines form an important part of the traditional diet and reflect the special African situation. They are cheap and easily available outside supermarkets and other retail outlets. Street vendors and hawkers who do not have cooling facilities or access to and washing facilities sell the products. The break in the cold chain, especially under South African climatic conditions, favours the multiplication and consequently the increase of numbers of Campylobacter bacteria already present in the products. The handling of such contaminated products in households and the potential for cross-contamination of other foods presents a high risk of infection to consumers. This research project concludes that Campylobacter is prevalent in poultry in South Africa and that the contamination of poultry meat and products with this organism could represent a health hazard for consumers in South Africa. It also emphasises the need for further research in this field. Copyright 2005, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bartkowiak-Higgo, A 2005, A survey of post-evisceration contamination of broiler carcasses and ready-to-sell livers and intestines (mala) with Campylobacter jejuni and Campylobacter coli in a high throughput South African poultry abattoir, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-02272006-101843 / > / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2005. / Paraclinical Sciences / unrestricted

Tick resistance to acaricides is an increasing problem in South Africa and poses a real economic threat to the livestock and veterinary pharmaceutical industries. New acaricides are extremely expensive to develop so the present acaricides should be seen as an ever-diminishing resource, which should be protected by all means possible. The main objective of the study was to detect the levels of tick resistance to acaricides at selected commercial and communal farms in South Africa. Also to compare the in vitro adult and larval test methods and to investigate acaricide management strategies which may increase the lifespan of the presently used acaricides. To meet these objectives a field survey (February 2000 to August 2001) was carried out at selected communal and commercial farms in the Eastern Cape and Northwest Provinces of South Africa to monitor levels of field tick resistance to acaricides. The larvae were originally obtained from engorged female A. hebraeum, B. decoloratus, R. appendiculatus and R. evertsi evertsi. The larvae were tested against different concentrations of amitraz, chlorfenvinphos and cypermethrin using the Shaw Larval Immersion Test (SLIT). Mortality dose data were subjected to probit analysis using a BMDP statistical package. Factors of resistance (FOR) were calculated by comparing the larval response of ticks from the field, which had been exposed to acaricides, with baseline data from very susceptible laboratory strains of ticks, on the basis of the LC50 values. On the communal farms high levels of tick resistance were detected to cypermethrin as well as partial resistance to chlorfenvinphos whilst no resistance was detected against amitraz. On the commercial farms, however, ticks were equally resistant to amitraz, cypermethrin and chlorfenvinphos. The populations of B. decoloratus on these farms had developed higher levels of resistance to the test acaricides than the equivalent R. evertsi evertsi, R. appendiculatus and A. hebraeum populations. Higher levels of tick resistance to amitraz was observed on commercial farms than on communal farms, however, there was no significant differences in tick resistance to chlorfenvinphos and cypermethrin at both the commercial and communal farms. It was surmised that inappropriate use of acaricides might have resulted in higher tick resistance to the currently available acaricides on the commercial as well as the communal farms. Correct acaricide usage may solve this problem to a limited extent. Comparative in vitro tests were also carried out on the larvae and adults of B. decoloratus to determine the susceptibility of this tick to different concentrations of the currently used acaricides, (amitraz, chlorfenvinphos and cypermethrin) at three commercial dairy farms, (“Brycedale”, “Sunny Grove” and “Welgevind”) near East London in the Eastern Cape Province of South Africa. Resistance of field strains of B. decoloratus were determined using the SLIT and the Adult Immersion Test (AIT) as the latter test took into account factors such as oviposition assessment and reproductive ability. At “Brycedale”, resistance to amitraz and chlorfenvinphos was detected with the AIT method. Emerging resistance to amitraz and resistance to chlorfenvinphos were also detected at “Brycedale” with the SLIT method. At “Sunny Grove” resistance was detected to cypermethrin and at “Welgevind” resistance was detected to chlorfenvinphos with the SLIT whilst no resistance was detected using AIT. It would appear that the B. decoloratus populations tested on these dairy farms were more resistant to chlorfenvinphos than to amitraz or cypermethrin. Variable results were obtained using the SLIT, the Reproductive Estimate Test (RET) and the Egg laying Test (ELT). Nearly 50% of the dairy farms sampled showed resistance to chlorfenvinphos and the majority had susceptible B. decoloratus populations to both amitraz and cypermethrin. “Brycedale” had a serious resistance problem whilst “Sunny Grove” and “Welgevind” dairies had much less resistance problems. At “Brycedale”, the SLIT, RET and ELT methods all recorded resistance to amitraz and chlorfenvinphos whilst cypermethrin resistance was also detected with the ELT. At “Sunny Grove”, the SLIT detected emerging resistance to chlorfenvinphos and resistance to cypermethrin while the other two test methods were negative. At “Welgevind” the SLIT detected resistance to chlorfenvinphos and the ELT resistance to cypermethrin whilst the RET did not detect any resistance at “Welgevind”. In general there was a good correlation between the RET and the ELT whilst in many cases there was poor correlation between the SLIT and the two AIT methods (RET and ELT). From this study it would appear that the ELT was a good method to detect resistance within seven days, as opposed to the 42 days required for the RET and the 60 days for the SLIT. The ELT and the RET could possibly be used as screening methods to detect acaricide resistance on farms whilst the SLIT would remain the test of choice for National surveys. In addition the ELT is less costly and does not require sophisticated equipment for field testing for resistance, compared with other in vitro test methods. This method, however, still needs to be validated and standardized for use in South Africa and the rest of Africa where tick control is important. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2002. / Veterinary Tropical Diseases / unrestricted

The main objective of the study was to investigate whether there were significant differences in prevalence of antibodies to Babesia bigemina and Babesia bovis between vaccinated and unvaccinated cattle in a tick-borne disease endemic area of South Africa. The study was carried out between August 2000 and June 2001, in the Northern Province of South Africa at Nooitgedacht ranch (24° 33’ S and 28° 36’ E), where calves were vaccinated against B. bigemina and B. bovis infections, and at Vlakplaas ranch (24° 58’ S and 28° 05’ E), where calves had not been vaccinated against these parasites. Sera were collected from cattle of different age groups at both ranches and the presence of antibodies against B. bigemina and B. bovisdetermined using the indirect fluorescent antibody (IFA) test. It was found that B. bovis was absent from both ranches while B. bigemina antibody was more prevalent in cattle at Vlakplaas (unvaccinated) than at Nooitgedacht (vaccinated). The difference in B. bigemina antibody response between the ranches may have been due to variations in tick populations. Vlakplaas, which had been operated for 14 years with relaxed tick control, probably had sufficient numbers of vector ticks for frequent transmission and maintenance of endemic stability to B. bigemina. At Nooitgedacht, however, livestock farming had been interrupted for three years before it was resumed in 1999 and it is postulated that the tick population had been substantially reduced due to lack of hosts to a level insufficient for the establishment and maintenance of endemic stability to B. bigemina. The vaccinated cattle and breeding cows might therefore have lost IFA reacting antibody titres due to low levels of superinfections. The findings show that an endemically stable situation to B. bigemina could be achieved by adapting a tick control method that allows sufficient number of ticks on cattle rather than relying entirely on intensive tick control and vaccination. Therefore, it may not be necessary to vaccinate calves against B. bigemina on ranches located in B. bigemina-endemic areas and stocked with Bos indicus cattle or their crosses. Key words: Babesia bigemina, Babesia bovis, bovine babesiosis, tick-borne diseases, endemic stability, immunization, antibody response, Brahman, Bonsmara, South Africa. / Dissertation (MSc (Veterinary Sciences))--University of Pretoria, 2001. / Veterinary Tropical Diseases / unrestricted

This thesis describes a two-component study undertaken in smallholder dairy systems of Central Kenya. One component characterized delivery systems for tick and tick-borne disease (TTBD) technologies including treatment packages, tick control products and vaccines, while the second component evaluated the important factors in their utilization by farmers. A combination of two economic analytical tools was used for the characterisation component. The first, the structure-conduct-performance (SCP) framework, was used to evaluate the performance of marketing systems and compare it to a perfectly competitive model, and the second, the new institutional economics (NIE) framework, was used to analyse the role of transaction costs in the delivery of products and services and their access by farmers. A probit model was applied to identify the specific factors that farmers consider in their choices of animal health services. Recommendations were made for the optimal pathways to deliver East Coast fever vaccines to smallholder farmers. The study was conducted in three phases. The first phase involved a cross- sectional survey of 344 smallholder dairy farmers in the central highlands of Kenya, using a structured questionnaire. These farms were selected on a gradient of market access, with high, medium and low market access represented by Kiambu, Nakuru and Nyandarua districts, respectively. The second phase involved an exhaustive survey of all service providers delivering animal health services in the study areas. The third phase involved working backwards through the marketing chain to the distributors and suppliers of technologies, as well as interviewing key informants at policy and institutional levels. Delivery of TTBD products and services was found to be highly competitive, mostly carried out by paravets (35% of the total) and stores (33%), particularly in rural areas. Vets (18%) had a higher distribution in peri-urban areas, and their limited distribution in rural areas raised the transaction costs associated with rural farmers’ search and screening for high quality services. There were no formal regulatory bodies supervising the quality of the products and services being supplied to farmers and no state restrictions existed on the type of service providers selling tick control products. Although pyrethrines (pour-ons) were only permitted for tsetse control, they were freely being sold to farmers for tick control. A live vaccine, the infection and treatment method (ITM) for ECF immunization, was available in the country but its sale was restricted to a single site, the Kenya Coast. Thus, this vaccine was not available in the study areas. The study identified three key problems that require specific policy intervention: i) poor access of services and products by farmers, with an undefined role of paravets who are presently under-utilized, ii) information asymmetries among farmers and the need to enforce service quality control of products and services, iii) lack of voice among smallholder farmers with no leverage for compensations in cases where they receive poor or inappropriate services. Several transaction costs were identified as constraining the utilization of animal health services by farmers, and ranged from information, through negotiation to monitoring costs. Farmers considered the ethnicity and the service quality (as determined by past performance) of the nearest service provider as important in their choices, and the density of service providers over a given radius around each farm as well as travel time to a service provider were crucial determinants in farmer decision-making. Using a combination of economic and epidemiological approaches, the study assessed supply and demand issues associated with delivery pathways for ECF vaccines among smallholder farmers. The supply-side component involved evaluating transaction costs associated with two ECF vaccines; ITM and a sub-unit vaccine under development, and identifying the appropriate role of public and private sector in delivery. The main constraints associated with ECF vaccine delivery and requiring appropriate policies included high information asymmetries faced by farmers, lack of appropriate quality control and limited accessibility to products and services by farmers. On the demand side, ECF risk was found to vary with cattle production systems and agro-ecology. Potential demand for vaccines was found to be high in both Nyandarua and Nakuru districts and relatively low in Kiambu, where zero-grazing reduces risk substantially. The study recommends utilization of paravets for ECF vaccine delivery as an effective means of reducing transaction costs by increasing service penetration especially in rural areas where the density of veterinarians tends to be low. / Thesis (PhD (Veterinary Sciences))--University of Pretoria, 2002. / Veterinary Tropical Diseases / unrestricted

Feedlot cattle are subjected to numerous stresses that impede on their growth performance and carcass quality. Stress also depletes the animal body with its nutrients subsequently leading to deficiencies. The aim of this study was to investigate the effect of selenium (Se) and chromium (Cr) on stress and subsequently on growth performance, carcass characteristics including meat colour and liver tissue minerals. It is thought that Se, as anti-oxidant and Cr effectiveness in glucose metabolism might be effective on these production parameters. Four experiments were conducted for that purpose. The first experiment consisted in the assessment of the response of animals to dietary supplement of 0.3 mg.kg –1 DM Se and 0.3 mg.kg –1 DM Cr in a 3x4 factorial design. Seventy-two steers were allocated to 12 pens of six animals each. The results showed no statistical difference in blood cortisol levels on day 0 (d 0). On d 04, cortisol concentrations were lower than on d 0 (P≤0.05) except for treatment “Se X Cr combination” (SEL/CHR). On d 42, the values were high again except for SEL/CHR that had very low cortisol values (P≤0.05). The plots of blood glucose concentrations were almost similar to those of blood cortisol. There was no carry-over effect of alleviation of stress on performance. It was suggested that the animal type used was not appropriate for feedlot. The carcass characteristics were not statistically different. Meat pH measurements were similar but the differences between pH taken on slaughter day (pH 1) and 24 hours later were different (P≤0.05) for CHR and SEL/CR. This suggests that Cr because of its effect on glycogen storage is more effective in maintaining an appropriate meat pH fall and subsequently a longer meat shelf life. The liver tissue mineral status of the animals was normal. However, supplemental Se increased significantly (P≤0.05) the liver tissue Ca, Mg, Co and Mn while Cr decreased the concentrations of Ca, Mg and Co. Selenium was positively correlated to Cu and P while Cr was negatively correlated to Co. There was no relationship between liver tissue mineral and production parameters. The second trial dealt with the meat colour. Twenty-four prime rib samples were randomly collected from the animals described in Experiment-1 in a 2x3x4 factorial design (two samples per pen). Samples were treated as described by Buys et al. (2000). The readings of metmyoglobin as an indication of meat discoloration were not different between treatments. However, the ratio of metmyoglobin over the rest of meat components showed that supplemental chromium (CHR) had a lower value (P≤0.05). Chromium might have permitted a better glucose utilisation and glycogen storage in muscle of live animal. This might have maintained an adequate drop in meat pH subsequently lowering the lipid peroxidation and preventing the accumulation of metmyoglobin. The third trial was aimed to verify the findings of Experiment-1 and to compare the effect of Cr sulphate to that of high-Cr yeast and their interactions with Se. Seventy-two weaner calves were allocated to six pens of 12 animals each. Cortisol and glucose concentrations were similar on d 0. On d 04 treatments SEL and Cr sulphate (ICH) had low values (P≤0.05) while on d 42, combined Se and organic Cr (SOC) tended to have low values. These results and those from Experiment-1 showed that Se is efficient in the alleviation of stress in the adaptation days on feed while combined Se and Cr treatments are more efficient in the production phase. The organic Cr is not more effective than Cr sulphate in alleviation of stress. The combination “Se and inorganic Cr” (SIC) had higher ADG and better P-FCR (P≤0.05) and it tended to have better carcass characteristics. Mineral concentrations were normal and similar. As seen in Experiment-1, treatment SEL highly (P≤0.01) increased liver Ca concentration. Chromium and most other mineral concentrations were not affected by supplemental Cr. Overall, organic Cr was not superior to Cr sulphate. Previous experiments indicated that combining Se to Cr might give better results. The fourth trial aimed to find the best combination. Thirty-six weaner steers were allocated to six pens of six animals each. There was no difference in cortisol levels but a tendency (P=0.1) was noted on d 47 with combined “sodium selenite x Cr sulphate” (ISIC) and “high-Se yeast x Cr sulphate” (OSIC) having low values. Blood glucose values were not different. Blood cortisol concentrations were positively correlated to glucose on d 47. Selenium and Cr did not significantly affect the overall growth efficiency of the steers but during the adaptation period, the controls and OSIC treatments had better ADG and PFCR. Treatments ISIC and “sodium selenite x organic Cr” (ISOC) had similar live weight whilst treatment OSIC had higher live weight than “organic Se x organic Cr” OSOC. The combined organic forms were better than the inorganic ones. The carcass parameters were not affected. However, ISIC tend to have higher carcass mass than ISOC; similarly, OSIC tended to perform better than OSOC. Higher liver tissue Se and Cr were due to supplemental Se and Cr (P≤0.05). Treatment ISIC had the highest liver Se levels (P≤0.05) in this experiment and in Experiment-3. Selenium did not interact with other elements. In contrast, Cr was negatively correlated to Fe and Mn and positively to Mg. Chromium tends to be negatively correlated to other minerals. Precautions might be recommended when feeding excessive Cr because Cr does not augment the liver concentration of other minerals (Chang et al., 1992; Anderson et al., 1997). / Thesis (PhD)--University of Pretoria, 2001. / Production Animal Studies / unrestricted

Bovine Respiratory disease (BRD) accounts for the highest proportion of morbidities and mortalities in feedlot cattle. Since both clinical and subclinical disease is known to affect growth performance, it is clear that both should be accounted for in estimating the overall effect of BRD on performance in feedlot cattle. To our knowledge there have been no studies estimating the true impact of BRD on the economy of the South African feedlot industry, including both the direct costs of treatment, labour and mortalities and the hidden costs of lower gains due to BRD. This was an observational study, utilising predominantly routinely collected data from two commercial cattle feedlots. Assessment of the effect of treatment for BRD on outcome variables (performance parameters and prevalence of lesions) took the form of a prospective cohort study. Assessment of the effect of lung lesions at slaughter on performance took the form of a cross-sectional study, in which the presence of lung lesions and performance parameters were recorded at slaughter. Assessment of the overall effect of BRD on performance was then done using a combined case definition (treatment for BRD and/or lung lesions present at slaughter). Slaughter data for 2036 animals were available for the final analysis. Mean average daily gain (ADG) for all animals was 1.504 kg for the period from processing to slaughter. Average days on feed (DOF) was 136 days. Peak incidence of respiratory disease in the feedlots occurred on Day 18 after arrival. A total of 22.7% of animals were treated for clinical respiratory disease. No mortalities occurred due to BRD during this period. A total of 42.8% of animals had lung lesions present at slaughter. Of animals never treated for respiratory disease, 38.5% had lung lesions at slaughter. Of animals that had lung lesions at slaughter, 69.5% had never been treated for respiratory disease. Using the combined case definition, the estimated incidence of BRD during this study was 52%. It was found that pulling for BRD was associated with an overall decrease in ADG of 19 g for the whole period in the feedlot. The presence of lung lesions (bronchopneumonia and/or adhesions/pleuritis) at slaughter was associated with a decrease in ADG of 27 g for the whole feeding period. The occurrence of BRD (using the combined case definition) was associated with a decrease in ADG of 28 g for the period from processing to slaughter. This translated into a hidden cost of R14.93 per animal in the feedlot. This was nearly equal to the direct variable cost/animal entering the feedlot of R15.40. The total loss due to BRD was estimated to be R30.30 per animal entering the feedlot with an estimated cost of about R40m per year to the South African feedlot industry. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2004. / Production Animal Studies / unrestricted

The objectives of the study were to compare the efficacy of six intramammary dry-cow antibiotic preparations for curing existing IMI and for preventing the introduction of new IMI during the dry period. The effect of factors such as parity, milk yield, udder depth, teat canal integrity, number of infected quarters per cow, quarter-site infections and somatic cell count at drying off on cure-rates and new IMI as well as the length of the dry period and rainfall during the dry period were examined. The possible influence of treatment on the SCC during the subsequent lactation was also examined. Prior to the study a herd survey was performed to determine the basic udder health status of the trial herd. Cows due for drying off were clinically evaluated for enrollment and randomly allocated to receive one of the six dry-cow intramammary products under investigation. The six products that were studied were Nafpenzal DC (procaine benzylpenicillin, nafcillin and dihydrostreptomycin), Rilexine 500 DC (cephalexin and neomycin sulphate), Orbenin Extra DC (cloxacillin), Cepravin Dry Cow (cephalonium), Bovaclox DC (cloxacillin and ampicillin) and Dispolac Dry Cow (procaine benzylpenicillin and dihydrostreptomycin). Quarter milk samples were collected at drying off, (prior to treatment), and 1 to 6 days after calving for determination of the SSC and presence of micro-organisms in the milk. Cows were closely observed during the dry period and udders were clinically examined on a weekly basis and post-calving till udder oedema disappeared. Data from 162 cows and 648 quarters are summarized. The following were determined · Prevalence of pathogens at drying off and post-calving · Overall cure-rate and new intramammary infection rate. · Comparative efficacy of dry-cow treatment on cure-rate and prevention of new IMI. · Effect of parity, milk yield at drying off, udder depth, teat canal integrity, SCC, quarter-site infection, number of infected quarters at drying off, length of the dry period and rainfall during the dry period. · Effect of treatment on three SCC post calving during the subsequent lactation. Clinical mastitis developed in two quarters of two cows (1,03%) during the dry period which was less than described in literature, and they were removed from the trial. The prevalence of pathogens at drying off was 29,78%, of which 7,87% and 21,91% were due to major and minor pathogens respectively. The prevalence of pathogens post-calving was 22,22%, a net reduction of 7,56%, of which 4,47% and 17,75% were due to major and minor pathogens respectively. The overall cure-rate was 83,94% for quarters and varied between 72,3% and 93,9% for the various products. The overall difference in the percentage of cases cured, compared to the different micro-organisms, was found to be only marginally significant (p<0,057). High cure- rates were observed for STA, SAG and non-agalactiae pathogenic streptococci compared to studies previously done, while lower cure-rates than described were observed with CNS. Antimicrobial products used in this trial differed substantially in their efficacy to cure Gram-positive IMI. Cure rates for Cepravin Dry Cow was 93,9%, Orbenin Extra DC 91,5%, Rilexine 500 DC 85,7%, Nafpenzal DC 79,2%, Bovaclox DC 75,0% and Dispolac Dry Cow 72,4%. Interestingly, but not of any significance, was an observation that the two products with the highest overall cure-rates both contained only one antimicrobial agent compared to the other 4 products which were combinations of two or more antimicrobials. There was no significant association between parity, milk yield, teat canal integrity, number of infected quarters per cow, quarter-site infections at drying off, length of the dry period and rainfall during the dry period and the cure-rate. However, there was a significant association between udder depth (p<0,0056) and SCC (p<0,005) at drying off and cure-rate. The cure-rate was significantly less in cows with udder depth scores of 1 and 2 or SCC of more than 750 000 cells per ml milk at drying off. The overall rate of new IMI during the dry period was 17,44%. The new intramammary infection rate for quarters which received dry-cow treatment varied between 13,4% and 24,1% for the different products. The majority (70,8%) of new IMI were caused by CNS during the dry period. Almost all (96,6%) major pathogens isolated post-calving were new IMI, while 74,1% of minor pathogens were new IMI. Antimicrobial products differed in their efficacy in preventing new IMI during the dry period. The percentages of new IMI observed in cows treated with the six products were: 13,2% for Cepravin Dry Cow, 16,3% for Rilexine 500 DC, 16,7% for Dispolac Dry Cow, 17,3% for Bovaclox DC, 21,4% for Nafpenzal DC and 25,9% for Orbenin Extra DC. The probability of quarters developing new IMI during the dry period was significantly increased when cows were dried off with milk yields higher than 18kg (p<0,0037) or had low udder depth (scores of 1 or 2) (p<0,0003). Higher parity cows (p<0,005) and those that had a teat canal score of 4 (p<0,039) and above at drying off were also at an increased risk for new IMI. Marginally significantly (p<0,06) more IMI were contracted on the left side of the udder than the right side of the udder and cows at drying off and cows with dry periods longer than 80 days had marginally (p<0,06) more new IMI during the dry period. A positive correlation was found between low SCC (<250 000 cell per ml milk) and number of infected quarters per cow and parity (less than 3 lactations) at drying off. There was no significant association between the SCC at drying off and new IMI during the dry period. Significantly fewer new IMI (p<0,05) were observed when no rain fell during the dry period, compared to cows that experienced rain during their dry period. A comparison between the six antibiotic intramammary dry-cow products in relation to their efficacy in curing existing IMI and preventing new IMI showed qualitative differences between them, ranked as follows: Dispolac Dry Cow was the most effective and Orbenin Extra dry the least effective in preventing new IMI with major pathogens and Cepravin Dry Cow was to most and Nafpenzal DC the least effective in preventing new IMI with minor pathogens. Cepravin Dry cow was the most effective in the overall prevention of new IMIduring the dry period. Due to the random selection of cows the percentage of IMI differed for each product at the start of the trial. To compensate for this initial variation, percentage point improvement from drying off until calving was calculated for each antimicrobial product, taking both the cure-rates and new IMI into account. The efficacy of antimicrobial products during the dry period differed substantially when percentage point improvements were utilised: from an increase in IMI post-calving of 11,73% with Nafpenzal DC to a decrease of more than 50% in IMI at calving with both Cepravin Dry Cow and Rilexine 500 DC. Cows dried off with Rilexine 500 DC had a significantly lower SCC for the first two months post-calving than those dried off with the other five products in this trial. It is concluded that a substantial difference in efficacy exists between antimicrobial intramammary dry-cow products in their ability to cure and prevent new IMI during the dry period. Dry cow therapy should form part of a holistic approach towards the dry period, which also includes cow factors, dry-cow management, micro-organisms and the environment of the dry cow. Cow factors (milk yields, udder depth, parity, TCS and quarter-site infections) mainly have an influence on new IMI but a few cow factors (udder depth and SCC) are associated with the cure-rate of IMI. Management and rainfall during the dry period mainly affected new IMI rather than the cure-rate of existing IMI. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2004. / Production Animal Studies / unrestricted

This study was motivated by the desire to make a difference in the world. A better understanding of how ancient peoples perceived the phenomenon of war, and how these perceptions were shaped by social values, can hold great value for contemporary peace processes. A large number of Old Testament passages can further be illuminated through a study of this nature. The problem can be summarised by the following question: ● Why did the ancient person positively regard war as an inevitable cultural phenomenon, while the contemporary Western person negatively regards war as an anomaly? The hypotheses are as follows: ● the social values of respectively the Western and the ancient world can explain why there is a discrepancy between their respective perceptions about war; ● a study of Joshua 23 can verify the results attained above. The purpose of this essay is: ● to determine whether the social values of respectively the Western and the ancient world can explain why there is a discrepancy between their respective perceptions about war; ● to determine whether a study of Joshua 23 can verify the results attained above. Chapter 1 introduces the study. Chapter 2 examines the difference between Western and ancient perceptions of war regarding the following social values: honour and shame, group-orientation, limited goods, purity. A synchronic exegesis of Joshua 23 follows in Chapter 3. During the course of this exegesis, the results of Chapter 2 will both illuminate and be verified by Joshua 23. Chapter 4 presents the interested student with guidelines for further study on this subject. The aim of this study is to promote peace in 2004 by illuminating Joshua 23. / Dissertation (MA (Ancient Languages and Culture Studies))--University of Pretoria, 2004. / Ancient Languages / unrestricted

Rural subsistence farming practices are the primary agricultural activity in northeastern KwaZulu-Natal, South Africa. Cattle in this area have long been affected by tsetse-borne trypanosome infections. The causative organism, Trypanosoma brucei brucei was first identified by Bruce in the late 1800’s. Approximately 120000 cattle fall within a tsetse (Glossina austeni and Glossina brevipalpis) belt common to Mozambique and South Africa. Between 1991 and 1994 cattle in this area were treated with homidium bromide, and dipped with cyhalothrin, in an attempt to control trypanosomosis. No control measures have been implemented since 1994, however, and trypanosomosis re-emerged as a threat to animal health. In order to determine the optimum control measure available, a longitudinal incidence study was conducted to evaluate three possible control options. Four sentinel herds were selected from populations exposed to similar trypanosome challenges. The baseline trypanosome incidence rate was determined for each herd, after which each herd was subjected to a different trypanosome control measure. Two of the herds were subjected to topical pyrethroid treatment (Cyfluthrin pour-on and Flumethrin plunge-dip) as vector-control measures, one herd was treated 6 weekly with an injectable trypanocidal drug (isometamidium hydrochloride), and one herd served as an untreated control group. Monthly incidence rates were determined using the ‘dark-ground buffy smear technique’. The monthly incidence rates were standardized in order to account for variation in trypanosomosis challenge between the 4 herds. The standardized rates were then compared and the impact of the control strategies was quantified using the Area Under The Curve method. The cost efficacy of each control strategy was evaluated based on a partial budget system. Both the cyfluthrin pour-on and the injectable trypanocide were cost effective and had a dramatic trypanosomosis control effect with the pour-on having the greater impact/ control. The flumethrin plunge-dip displayed moderate trypanosomosis control properties, but proved not to be cost effective. / Dissertation (MSc (Veterinary Science))--University of Pretoria, 2004. / Production Animal Studies / unrestricted

The addition of prostatic fluid to intravaginally inseminated frozen-thawed semen resulted in an increase in pregnancy rate in bitches when compared with frozen-thawed semen inseminated on its own (Nöthling and Volkmann, 1993). However, the volume and viscosity of the inseminates varied greatly, which may have caused the improvement in fertility. Sperm TALP is a sperm-friendly fluid used extensively inin vitro processes. It was modified to exclude albumin to avoid any potentially beneficial effect. Twenty-eight young, healthy German shepherd bitches were inseminated with frozen-thawed semen to which either prostatic fluid (Group P) or albumin-free TALP (Group T) was added to provide an insemination volume of 7 ml. All bitches were inseminated daily from the onset of the appearance of shrunken angular folds on vaginoscopic evaluation until the day prior to diestrus as confirmed by cytological evaluation. Approximately 50 million progressively motile sperm was used per insemination. The semen was inseminated intravaginally after the addition of the appropriate fluid. Bitches were spayed 3 weeks after the onset of dioestrus and the number of conceptuses and corpora lutea counted. The non-resorbed conceptuses were taken as the litter size. The number of corpora lutea did not differ between the groups (n=25, P=0.496). The pregnancy rate between the groups did not differ. Among pregnant bitches, Group P (n=13) had significantly higher litter sizes than Group T (n=12) (P = 0.036). For the 13 bitches that received prostatic fluid, there were 139 corpora lutea and 80 conceptuses whereas, for the 12 bitches that received albumin-free TALP, there were 117 corpora lutea and 44 conceptuses (Chi-squared, P=0.002). Prostatic fluid has a positive influence on the fertility of frozen-thawed sperm more than by merely increasing the volume or decreasing the viscosity of the inseminate. The exact mechanism of its influence remains unknown. / Dissertation (MMedVet (Gyn))--University of Pretoria, 2002. / Production Animal Studies / unrestricted