Abalone have been cultured in South Africa for seventeen years. The growing industry has led to i... more Abalone have been cultured in South Africa for seventeen years. The growing industry has led to increased intensification. Farms are concentrated in certain areas, notably Hermanus on the South coast, and may be close to wild abalone populations and processing facilities. These factors contribute to increased risk of disease emergence. Data on parasite prevalence generated from the abalone health management program between 2000 and 2004 was analysed for trends. Abalone were sampled systematically from participating farms and subjected to gross and histological examination. Data on age, size, gonad development, diet and type of system were recorded. This paper presents the most significant results for gut protozoa, digestive gland protozoa and rickettsia like prokaryotes, which are all gut associated. Prevalence was found to increase with increasing age and size. Higher parasite prevalences were found on the West coast than on the South coast, and outside Hermanus compared to within Hermanus, suggesting that concentration of farms is not leading to increased prevalence. Gut associated parasites were significantly more prevalent in animals fed on kelp than artificial feed. It was found that animals younger than 24 months are more at risk of infection when fed kelp than older animals. The results indicate that separation of age groups, removal of poor performers and use of artificial feed, especially in younger animals, are likely to reduce risk of infection with gut associated parasites.
The high-performance liquid chromatographic method published by Aliu &amp... more The high-performance liquid chromatographic method published by Aliu & Odegaard (1983) was found to give poor peak separation when used to determine plasma diminazene concentrations in cattle. Before bioequivalence studies could be carried out, the method had to be modified. Solid-phase extraction with acetonitrile/0.025 M Na-octane sulphonate and 2% acetic acid as eluent, followed by sample concentration, gave recoveries of > 90% for diminazene and the internal standard. A mobile phase of acetonitrile/0,005 M Na-octane sulphonate, 0.1% triethylamine, pH 3.2 with acetic acid on a Nova Pak C18 column was used for the analysis. Wavelength switching was used to determine the internal standard (imidocarb) and diminazene at their respective wavelengths of maximum absorbance, resulting in a fivefold increase in the limit of detection for diminazene. The modified method attained a detection limit of 2 ng.m.-1 (peak 4x baseline noise), limit of quantitation of 10 ng.m.-1 (coefficient of variation < 15%) and an accuracy of > 96% over the range from 10-5000 ng.m.-1.
Journal of the South African Veterinary Association, 1999
Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming... more Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming systems in South Africa are described. On 2 farms, pigs constituted the main enterprise with cattle and sheep of secondary importance. On each of these 2 farms, abortion due to L. pomona in sows was confirmed by culture, and antibody titres to pomona were detected in cattle, sheep, horses and dogs. On the 3rd farm, a piggery was ofsecondary importance to cattle farming. Abortion and death in cows occurred on this farmand serology showed titres to various serovars, including pomona. L. pomona was also isolated from bovine urine, an aborted bovine foetus and kidneys from slaughtered pigs. This particular case study was regarded as clinically atypical in that adult Jersey cattle died of acute leptospirosis in a semiarid region of South Africa. In all 3 case studies, the poor management of pig effluent and of the drinking water and its sources played a pivotal role in the transmission of th...
Journal of the South African Veterinary Association, 2007
A questionnaire survey of 315 cattle owners from the rural districts of KwaZulu-Natal was carried... more A questionnaire survey of 315 cattle owners from the rural districts of KwaZulu-Natal was carried out. The aim of the survey was to improve our understanding of local farmers' perceptions and practices of animal disease prevention and control and to establish the extent of their relationship with veterinary services. The survey showed that many owners practice preventive measures such as deworming, tick control and vaccination. Traditional medicines were in use by over half the respondents (58.9 %). Diseases are regarded as an important management problem (56.1 %); ticks, worms and diarrhoea dominated the mentioned health problems in cattle. Veterinary services still play an important role and are a frequent source of advice to owners. The findings of the survey and their context are discussed.
Journal of the South African Veterinary Association, 2010
Epidemiological analyses in time and space were carried out on all animal rabies cases reported i... more Epidemiological analyses in time and space were carried out on all animal rabies cases reported in South Africa for the period 1993 - 2005. Validation of state veterinary records was done by comparing these with data from the 2 diagnostic laboratories mandated to test for animal rabies. A discrepancy between state veterinary records and laboratory results was found and is discussed. The total number of positive rabies cases reported to veterinary services between 1993 and 2005 was 4767. During this period the proportion of domestic animal rabies had increased to 79% (19% more than for the period 1980 - 1994), with 59% of the total cases being domestic dogs. Of the domestic animal cases 74% were canine and only 21% were bovine; when compared to the data from 1985 - 1994 there was an increase of 6% of rabies in canine and a 3% decrease in bovine cases. A disturbing trend is the increase in the incidence of rabies over the last 16 years in provinces neighbouring KwaZulu-Natal province,...
A field trial compared a modified Pasteurella haemolytica biotype A serotype 1 leukotoxin vaccine... more A field trial compared a modified Pasteurella haemolytica biotype A serotype 1 leukotoxin vaccine to a commercial vaccine during March±July 1995 in a Natal Midlands, South African, feedlot. Weaners/long weaners purchased by the feedlot were allocated systematically into test vaccine and control vaccine groups of 1241 and 1240 head, respectively, and fed in groups of approximately 200 head. Morbidity and mortality were monitored until the animals were marketed. Details of pleuritis and pneumonia at veterinary meat inspection were recorded for 409 testvaccinated and 424 control-vaccinated cattle. An increase in morbidity but not mortality risk of respiratory disease was shown between test (13.8% morbidity) and control (11.4% morbidity) groups. Cattle with a processing weight <245 kg were 1.4 times more likely to develop respiratory diseases than cattle with a processing weight !245 kg. Cattle bought on auction were 1.6 times more likely to develop respiratory disease than cattle bought at private sales.
In today's world, emerging and re-emerging diseases have a significant impact on global economies... more In today's world, emerging and re-emerging diseases have a significant impact on global economies and public health, and with bioterrorism a constant threat this has become a very topical subject in recent years. Bernard Vallat, director general of the OIE, made the statement, "As a result of globalisation and climate change we are currently facing an unprecedented worldwide impact of emerging and re-emerging animal diseases and zoonoses". He is not alone in this thinking, but are we facing an unprecedented impact of diseases and are globalisation and climate change the main driving forces? This paper examines some historical disease outbreaks and the factors that played a role in their emergence and compares these with recent emerging diseases. In doing so it highlights certain challenges that face livestock producers and decision makers today as they grapple with emerging diseases. One of the driving forces for the emergence of diseases is translocation of people and their livestock and this has often been coupled with invading armies or peoples, political unrest and a concurrent environment of socio-economic upheaval. Contact between wild animals, domestic animals and people is another driving force involving the interaction between naïve population groups that induces the emergence of new diseases. Pandemics are not new to human society and nor are many of the driving forces that caused them to occur in the past; what has changed is our increased knowledge and awareness of disease dynamics, allowing identification of challenges for the future and ways of addressing these. Modern farming practices often serve to amplify emerging infectious diseases and modern trade and transport mechanisms and routes have served to sometimes accelerate the spread of disease. How can we reduce the risks and should we only be worried about emerging infectious diseases or are emerging non-communicable diseases just as important in our modern society? This paper serves to explain some of the reasons for the emergence of diseases and to try and answer some of the pressing questions that confront livestock producers today.
A door-to-door prevalence study of feline immunodeficiency virus in an Australian suburb techniqu... more A door-to-door prevalence study of feline immunodeficiency virus in an Australian suburb technique does not amount to an endorsement of its value or quality, or the claims made by its manufacturer. those of the authors and the inclusion in this publication of material relating to a particular product, method or of animals and interpretation of published materials lies with the veterinary practitioner. The opinions expressed are from actions or decisions based on information contained in this publication; ultimate responsibility for the treatment arising country. The authors, editors, owners and publishers do not accept any responsibility for any loss or damage advertising material, it is the responsibility of the reader to check that the product is authorised for use in their own bear this in mind and be aware of the prescribing laws pertaining to their own country. Likewise, in relation to Furthermore, drugs may be mentioned that are licensed for human use, and not for veterinary use. Readers need to formulations that are not available or licensed in the individual reader's own country.
A sentinel herd of 30 Brahman Cross cattle was run as an extensive beef commercial herd and exper... more A sentinel herd of 30 Brahman Cross cattle was run as an extensive beef commercial herd and experimental cohort on a vanadium mining property over a five-year period. The cattle were farmed as two groups. A high exposure group that grazed downwind in an area immediately adjacent to the processing plant and a low exposure group whose grazing began approximately 2 km upwind of the processing plant. A primary objective of the study was to investigate whether a long-term animal sentinel system for the vanadium mining industry could act as a monitoring system for pollution problems and thus address the concerns of surrounding farmers.
In 1964, Brucella was isolated from rodents trapped in Wooroonooran National Park (WNP), in North... more In 1964, Brucella was isolated from rodents trapped in Wooroonooran National Park (WNP), in Northern Queensland, Australia. Genotyping of bacterial isolates in 2008 determined that they were a novel Brucella species. This study attempted to reisolate this species of Brucella from rodents living in the boundary area adjacent to WNP and to establish which endo- and ecto-parasites and bacterial agents were being carried by non-indigenous rodents at this interface. Seventy non-indigenous rodents were trapped [Mus musculus (52), Rattus rattus (17) and Rattus norvegicus (1)], euthanized and sampled on four properties adjacent to the WNP in July 2012. Organ pools were screened by culture for Salmonella, Leptospira and Brucella species, real-time PCR for Coxiella burnetii and conventional PCR for Leptospira. Collected ecto- and endo-parasites were identified using morphological criteria. The percentage of rodents carrying pathogens were Leptospira (40%), Salmonella choleraesuis ssp. arizona...
The Onderstepoort journal of veterinary research, 1991
Pathological findings and liver and kidney analyses confirmed that cattle had died of chronic cop... more Pathological findings and liver and kidney analyses confirmed that cattle had died of chronic copper poisoning on a farm in the north-eastern Transvaal. This is the first known published record of chronic copper intoxication of cattle in southern Africa. An epidemiological study revealed that a source of copper was air pollution which could have arisen from a nearby copper smelting unit. Buffalo and impala in an adjacent area of the Kruger National Park were found to have significantly higher liver copper levels than animals elsewhere in the Park. Prophylactic licks, containing zinc sulphate and sulphur, seemed to be successful in protecting cattle against the effects of the copper in the contaminated grazing.
A disease outbreak investigation was conducted in western Queensland to investigate a rare suspec... more A disease outbreak investigation was conducted in western Queensland to investigate a rare suspected outbreak of pyrrolizidine alkaloid (PA) toxicosis in horses. Thirty five of 132 horses depastured on five properties on the Mitchell grass plains of western Queensland died in the first six months of 2010. Clinical-pathological findings were consistent with PA toxicosis. A local variety of Crotalaria medicaginea was the only hepatotoxic plant found growing on affected properties. Pathology reports and departure and arrival dates of two brood mares provided evidence of a pre wet season exposure period. All five affected properties experienced a very dry spring and early summer preceded by a large summer wet season. The outbreak was characterised as a point epidemic with a sudden peak of deaths in March followed by mortalities steadily declining until the end of June. The estimated morbidity (serum IGG>50IU/L) rate was 76%. Average crude mortality was 27% but higher in young horses ...
The Onderstepoort journal of veterinary research, 2012
An initial census of layer farms in Khartoum State, Sudan, was carried out in late 2007 and early... more An initial census of layer farms in Khartoum State, Sudan, was carried out in late 2007 and early 2008 and found that there were 252 layer farms with a total population of 2 221 800 birds. This paper reports the findings of the census. Based on this information, a structured questionnaire survey of 92 farms was then conducted in the state in April 2008 to collect data on antibiotic usage, demographic data and public health awareness. Ninety-eight per cent of participating farms comprised open-sided houses. It was found that 49% of the farms surveyed were on antibiotic treatment when the survey was conducted, whilst 59% of the farms had used antibiotics within the last 3 months. The study found that farmers and producers had a lack of knowledge about antimicrobial residues, their withdrawal periods and the risk posed by the consumption of these residues. The study also concluded that traditional farming systems in Sudan relied heavily on antimicrobial medication to control disease an...
The Onderstepoort journal of veterinary research, 1994
An epidemiological investigation into an "illthrift" problem occurring on a dairy farm ... more An epidemiological investigation into an "illthrift" problem occurring on a dairy farm adjacent to an alloy-processing unit, established that the probable cause of the problem was chronic vanadium poisoning. The disease manifested initially in animals 4-18 months old which showed emaciation, chronic diarrhoea and, in some cases, rhinitis, conjunctivitis and recumbency followed by death. Post-mortem (n = 17) and clinical-pathology findings (n = 60) indicated that malabsorption and immunosuppression were the basis of the pathogenesis in affected animals. Eight months after the commencement of the investigation, adult cows began showing evidence of emaciation, reduced milk production and an apparent increase in the number of abortions, stillbirths and dystocias. Over a 2-year period, 134 surface-soil samples, 134 subsoil samples and 134 grass samples from the farm were analysed for various fractions of vanadium. Thirty-four of each of these samples were collected at different...
Abalone have been cultured in South Africa for seventeen years. The growing industry has led to i... more Abalone have been cultured in South Africa for seventeen years. The growing industry has led to increased intensification. Farms are concentrated in certain areas, notably Hermanus on the South coast, and may be close to wild abalone populations and processing facilities. These factors contribute to increased risk of disease emergence. Data on parasite prevalence generated from the abalone health management program between 2000 and 2004 was analysed for trends. Abalone were sampled systematically from participating farms and subjected to gross and histological examination. Data on age, size, gonad development, diet and type of system were recorded. This paper presents the most significant results for gut protozoa, digestive gland protozoa and rickettsia like prokaryotes, which are all gut associated. Prevalence was found to increase with increasing age and size. Higher parasite prevalences were found on the West coast than on the South coast, and outside Hermanus compared to within Hermanus, suggesting that concentration of farms is not leading to increased prevalence. Gut associated parasites were significantly more prevalent in animals fed on kelp than artificial feed. It was found that animals younger than 24 months are more at risk of infection when fed kelp than older animals. The results indicate that separation of age groups, removal of poor performers and use of artificial feed, especially in younger animals, are likely to reduce risk of infection with gut associated parasites.
The high-performance liquid chromatographic method published by Aliu &amp;amp;amp;amp;amp;amp... more The high-performance liquid chromatographic method published by Aliu &amp;amp;amp;amp;amp;amp;amp; Odegaard (1983) was found to give poor peak separation when used to determine plasma diminazene concentrations in cattle. Before bioequivalence studies could be carried out, the method had to be modified. Solid-phase extraction with acetonitrile/0.025 M Na-octane sulphonate and 2% acetic acid as eluent, followed by sample concentration, gave recoveries of &amp;amp;amp;amp;amp;amp;gt; 90% for diminazene and the internal standard. A mobile phase of acetonitrile/0,005 M Na-octane sulphonate, 0.1% triethylamine, pH 3.2 with acetic acid on a Nova Pak C18 column was used for the analysis. Wavelength switching was used to determine the internal standard (imidocarb) and diminazene at their respective wavelengths of maximum absorbance, resulting in a fivefold increase in the limit of detection for diminazene. The modified method attained a detection limit of 2 ng.m.-1 (peak 4x baseline noise), limit of quantitation of 10 ng.m.-1 (coefficient of variation &amp;amp;amp;amp;amp;amp;lt; 15%) and an accuracy of &amp;amp;amp;amp;amp;amp;gt; 96% over the range from 10-5000 ng.m.-1.
Journal of the South African Veterinary Association, 1999
Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming... more Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming systems in South Africa are described. On 2 farms, pigs constituted the main enterprise with cattle and sheep of secondary importance. On each of these 2 farms, abortion due to L. pomona in sows was confirmed by culture, and antibody titres to pomona were detected in cattle, sheep, horses and dogs. On the 3rd farm, a piggery was ofsecondary importance to cattle farming. Abortion and death in cows occurred on this farmand serology showed titres to various serovars, including pomona. L. pomona was also isolated from bovine urine, an aborted bovine foetus and kidneys from slaughtered pigs. This particular case study was regarded as clinically atypical in that adult Jersey cattle died of acute leptospirosis in a semiarid region of South Africa. In all 3 case studies, the poor management of pig effluent and of the drinking water and its sources played a pivotal role in the transmission of th...
Journal of the South African Veterinary Association, 2007
A questionnaire survey of 315 cattle owners from the rural districts of KwaZulu-Natal was carried... more A questionnaire survey of 315 cattle owners from the rural districts of KwaZulu-Natal was carried out. The aim of the survey was to improve our understanding of local farmers&#39; perceptions and practices of animal disease prevention and control and to establish the extent of their relationship with veterinary services. The survey showed that many owners practice preventive measures such as deworming, tick control and vaccination. Traditional medicines were in use by over half the respondents (58.9 %). Diseases are regarded as an important management problem (56.1 %); ticks, worms and diarrhoea dominated the mentioned health problems in cattle. Veterinary services still play an important role and are a frequent source of advice to owners. The findings of the survey and their context are discussed.
Journal of the South African Veterinary Association, 2010
Epidemiological analyses in time and space were carried out on all animal rabies cases reported i... more Epidemiological analyses in time and space were carried out on all animal rabies cases reported in South Africa for the period 1993 - 2005. Validation of state veterinary records was done by comparing these with data from the 2 diagnostic laboratories mandated to test for animal rabies. A discrepancy between state veterinary records and laboratory results was found and is discussed. The total number of positive rabies cases reported to veterinary services between 1993 and 2005 was 4767. During this period the proportion of domestic animal rabies had increased to 79% (19% more than for the period 1980 - 1994), with 59% of the total cases being domestic dogs. Of the domestic animal cases 74% were canine and only 21% were bovine; when compared to the data from 1985 - 1994 there was an increase of 6% of rabies in canine and a 3% decrease in bovine cases. A disturbing trend is the increase in the incidence of rabies over the last 16 years in provinces neighbouring KwaZulu-Natal province,...
A field trial compared a modified Pasteurella haemolytica biotype A serotype 1 leukotoxin vaccine... more A field trial compared a modified Pasteurella haemolytica biotype A serotype 1 leukotoxin vaccine to a commercial vaccine during March±July 1995 in a Natal Midlands, South African, feedlot. Weaners/long weaners purchased by the feedlot were allocated systematically into test vaccine and control vaccine groups of 1241 and 1240 head, respectively, and fed in groups of approximately 200 head. Morbidity and mortality were monitored until the animals were marketed. Details of pleuritis and pneumonia at veterinary meat inspection were recorded for 409 testvaccinated and 424 control-vaccinated cattle. An increase in morbidity but not mortality risk of respiratory disease was shown between test (13.8% morbidity) and control (11.4% morbidity) groups. Cattle with a processing weight <245 kg were 1.4 times more likely to develop respiratory diseases than cattle with a processing weight !245 kg. Cattle bought on auction were 1.6 times more likely to develop respiratory disease than cattle bought at private sales.
In today's world, emerging and re-emerging diseases have a significant impact on global economies... more In today's world, emerging and re-emerging diseases have a significant impact on global economies and public health, and with bioterrorism a constant threat this has become a very topical subject in recent years. Bernard Vallat, director general of the OIE, made the statement, "As a result of globalisation and climate change we are currently facing an unprecedented worldwide impact of emerging and re-emerging animal diseases and zoonoses". He is not alone in this thinking, but are we facing an unprecedented impact of diseases and are globalisation and climate change the main driving forces? This paper examines some historical disease outbreaks and the factors that played a role in their emergence and compares these with recent emerging diseases. In doing so it highlights certain challenges that face livestock producers and decision makers today as they grapple with emerging diseases. One of the driving forces for the emergence of diseases is translocation of people and their livestock and this has often been coupled with invading armies or peoples, political unrest and a concurrent environment of socio-economic upheaval. Contact between wild animals, domestic animals and people is another driving force involving the interaction between naïve population groups that induces the emergence of new diseases. Pandemics are not new to human society and nor are many of the driving forces that caused them to occur in the past; what has changed is our increased knowledge and awareness of disease dynamics, allowing identification of challenges for the future and ways of addressing these. Modern farming practices often serve to amplify emerging infectious diseases and modern trade and transport mechanisms and routes have served to sometimes accelerate the spread of disease. How can we reduce the risks and should we only be worried about emerging infectious diseases or are emerging non-communicable diseases just as important in our modern society? This paper serves to explain some of the reasons for the emergence of diseases and to try and answer some of the pressing questions that confront livestock producers today.
A door-to-door prevalence study of feline immunodeficiency virus in an Australian suburb techniqu... more A door-to-door prevalence study of feline immunodeficiency virus in an Australian suburb technique does not amount to an endorsement of its value or quality, or the claims made by its manufacturer. those of the authors and the inclusion in this publication of material relating to a particular product, method or of animals and interpretation of published materials lies with the veterinary practitioner. The opinions expressed are from actions or decisions based on information contained in this publication; ultimate responsibility for the treatment arising country. The authors, editors, owners and publishers do not accept any responsibility for any loss or damage advertising material, it is the responsibility of the reader to check that the product is authorised for use in their own bear this in mind and be aware of the prescribing laws pertaining to their own country. Likewise, in relation to Furthermore, drugs may be mentioned that are licensed for human use, and not for veterinary use. Readers need to formulations that are not available or licensed in the individual reader's own country.
A sentinel herd of 30 Brahman Cross cattle was run as an extensive beef commercial herd and exper... more A sentinel herd of 30 Brahman Cross cattle was run as an extensive beef commercial herd and experimental cohort on a vanadium mining property over a five-year period. The cattle were farmed as two groups. A high exposure group that grazed downwind in an area immediately adjacent to the processing plant and a low exposure group whose grazing began approximately 2 km upwind of the processing plant. A primary objective of the study was to investigate whether a long-term animal sentinel system for the vanadium mining industry could act as a monitoring system for pollution problems and thus address the concerns of surrounding farmers.
In 1964, Brucella was isolated from rodents trapped in Wooroonooran National Park (WNP), in North... more In 1964, Brucella was isolated from rodents trapped in Wooroonooran National Park (WNP), in Northern Queensland, Australia. Genotyping of bacterial isolates in 2008 determined that they were a novel Brucella species. This study attempted to reisolate this species of Brucella from rodents living in the boundary area adjacent to WNP and to establish which endo- and ecto-parasites and bacterial agents were being carried by non-indigenous rodents at this interface. Seventy non-indigenous rodents were trapped [Mus musculus (52), Rattus rattus (17) and Rattus norvegicus (1)], euthanized and sampled on four properties adjacent to the WNP in July 2012. Organ pools were screened by culture for Salmonella, Leptospira and Brucella species, real-time PCR for Coxiella burnetii and conventional PCR for Leptospira. Collected ecto- and endo-parasites were identified using morphological criteria. The percentage of rodents carrying pathogens were Leptospira (40%), Salmonella choleraesuis ssp. arizona...
The Onderstepoort journal of veterinary research, 1991
Pathological findings and liver and kidney analyses confirmed that cattle had died of chronic cop... more Pathological findings and liver and kidney analyses confirmed that cattle had died of chronic copper poisoning on a farm in the north-eastern Transvaal. This is the first known published record of chronic copper intoxication of cattle in southern Africa. An epidemiological study revealed that a source of copper was air pollution which could have arisen from a nearby copper smelting unit. Buffalo and impala in an adjacent area of the Kruger National Park were found to have significantly higher liver copper levels than animals elsewhere in the Park. Prophylactic licks, containing zinc sulphate and sulphur, seemed to be successful in protecting cattle against the effects of the copper in the contaminated grazing.
A disease outbreak investigation was conducted in western Queensland to investigate a rare suspec... more A disease outbreak investigation was conducted in western Queensland to investigate a rare suspected outbreak of pyrrolizidine alkaloid (PA) toxicosis in horses. Thirty five of 132 horses depastured on five properties on the Mitchell grass plains of western Queensland died in the first six months of 2010. Clinical-pathological findings were consistent with PA toxicosis. A local variety of Crotalaria medicaginea was the only hepatotoxic plant found growing on affected properties. Pathology reports and departure and arrival dates of two brood mares provided evidence of a pre wet season exposure period. All five affected properties experienced a very dry spring and early summer preceded by a large summer wet season. The outbreak was characterised as a point epidemic with a sudden peak of deaths in March followed by mortalities steadily declining until the end of June. The estimated morbidity (serum IGG>50IU/L) rate was 76%. Average crude mortality was 27% but higher in young horses ...
The Onderstepoort journal of veterinary research, 2012
An initial census of layer farms in Khartoum State, Sudan, was carried out in late 2007 and early... more An initial census of layer farms in Khartoum State, Sudan, was carried out in late 2007 and early 2008 and found that there were 252 layer farms with a total population of 2 221 800 birds. This paper reports the findings of the census. Based on this information, a structured questionnaire survey of 92 farms was then conducted in the state in April 2008 to collect data on antibiotic usage, demographic data and public health awareness. Ninety-eight per cent of participating farms comprised open-sided houses. It was found that 49% of the farms surveyed were on antibiotic treatment when the survey was conducted, whilst 59% of the farms had used antibiotics within the last 3 months. The study found that farmers and producers had a lack of knowledge about antimicrobial residues, their withdrawal periods and the risk posed by the consumption of these residues. The study also concluded that traditional farming systems in Sudan relied heavily on antimicrobial medication to control disease an...
The Onderstepoort journal of veterinary research, 1994
An epidemiological investigation into an "illthrift" problem occurring on a dairy farm ... more An epidemiological investigation into an "illthrift" problem occurring on a dairy farm adjacent to an alloy-processing unit, established that the probable cause of the problem was chronic vanadium poisoning. The disease manifested initially in animals 4-18 months old which showed emaciation, chronic diarrhoea and, in some cases, rhinitis, conjunctivitis and recumbency followed by death. Post-mortem (n = 17) and clinical-pathology findings (n = 60) indicated that malabsorption and immunosuppression were the basis of the pathogenesis in affected animals. Eight months after the commencement of the investigation, adult cows began showing evidence of emaciation, reduced milk production and an apparent increase in the number of abortions, stillbirths and dystocias. Over a 2-year period, 134 surface-soil samples, 134 subsoil samples and 134 grass samples from the farm were analysed for various fractions of vanadium. Thirty-four of each of these samples were collected at different...
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Papers by Bruce Gummow