Trichostrongylus colubriformis is an important cause of parasitic gastroenteritis in ruminants, w... more Trichostrongylus colubriformis is an important cause of parasitic gastroenteritis in ruminants, where it causes protracted diarrhoea, rapid loss of weight, loss of production and death. The in vitro efficacy of extracts of Peltophorum africanum was determined against this parasitic nematode. Eggs and larvae of T. colubriformis were incubated at 23°C in the extracts of the leaf, bark and root of
In the veterinary industry, long acting oxytetracycline formulations are loosely referred to as t... more In the veterinary industry, long acting oxytetracycline formulations are loosely referred to as those formulations that only require a single dose at 20 mg/kg to achieve clinical cure and to be repeated after three days only if required. Short acting oxytetracycline formulations are recommended for use once a day for four days, at a dose of 10 mg/kg IV and 10mg/kg IM on day one, 10 mg/kg IM on day two and 5 mg/kg IM on days three and four. The primary objective of this study is to demonstrate that, based on pharmacokinetics, a double dose of a conventional short acting, 135mg/ml formulation of oxytetracycline has a longer action than a single dose of the same formulation. As a secondary objective the efficacy and safety of a single, double dose of a conventional oxytetracycline formulation are compared to multiple, single doses of a conventional formulation as well against a single dose of a long-acting formulation. Factors that influence the duration of action of a parenteral oxyte...
Journal of the South African Veterinary Association, Dec 7, 1999
The halogenated salicylanilides are a large group of compounds developed mainly for their antipar... more The halogenated salicylanilides are a large group of compounds developed mainly for their antiparasitic activity in animals. Several halogenated salicylanilides with potent antiparasitic activity have been synthesised of which only closantel, niclosamide, oxyclozanide, rafoxanide and resorantel are commercially available. Closantel and rafoxanide, which represent the most important drugs in the group, are used extensively for the control of Haemonchus spp. and Fasciola spp. infestations in sheep and cattle and Oestrus ovis in sheep in many parts of the world. Niclosamide is used extensively for its anticestodal activity in a wide range of animals. Antiparasitic activity of the halogenated salicylanilides has also been demonstrated against a large number of other internal parasites, in particular haematophagous helminths, and external parasites including ticks and mites, in a variety of animal species. Several cases of toxicity and mortality have been reported for closantel and rafoxanide in sheep and goats. Their unique pharmacokinetic behaviour appears to play an important role in the efficacy and safety of these compounds. The chemical and physical characteristics, mode of action, pharmacokinetics, antiparasitic activity and toxicity of the halogenated salicylanilides in animals are reviewed.
The Onderstepoort Journal of Veterinary Research, Jun 1, 2000
Morphological changes associated with rumino-reticular development was compared in two groups of ... more Morphological changes associated with rumino-reticular development was compared in two groups of SA Mutton Merino lambs (n = 12) fed different diets at 3-5 weeks, 17-19 weeks and 31-33 weeks of age. Diet groups were identified as MMH or MHH according to the sequence at which the full-milk replacement (M) or hay (H) diet were fed to the lambs over the three study phases (phases I, II and III) preceding each age period. Prominent differences in the morphology (size and volume) and function (pH , proteolytic activity and microbial population) of the rumino-reticulum were observed in indicator lambs (n = 2) killed at every age period and also between milk-fed and hay-fed lambs. The size of the rumino-reticulum was rudimentary at 3-5 weeks of age and remained underdeveloped in lambs at 17-19 weeks of age which had received a full-milk replacement diet during phase II. One lamb, slaughtered at 3 weeks of age, showed a large distended rumen with severe sloughing of the surface cells of the stratum corneum. The size of the rumino-reticulum increased in size (2 x) in lambs which were fed hay relative to the milk-fed lambs during phase II and reached adult proportions in all lambs at 31-33 weeks of age. Ultrastructural examination showed that rumen papillae were more developed in lambs fed hay during phase II when compared to those of milk-fed lambs. Rumen papillae were best developed in phase III Iambs.
Two anaesthetized sheep were intoxicated with epoxyscillirosidin, the main cardio-active bufadien... more Two anaesthetized sheep were intoxicated with epoxyscillirosidin, the main cardio-active bufadienolide, extracted from Homeria pallida (Natal yellow tulp). The epoxyscillirosidin was injected intravenously as a bolus of 50 micrograms/kg, followed 30 min later by a continuous infusion in a normal saline drip (0.9% NaCl) at 25 micrograms/kg/h. In addition, another two conscious sheep were poisoned by intraruminal dosing of 1,25 g/kg of dried H. pallida plant material. Electrocardiograms, heart and respiratory rates and venous-acid-base levels were recorded prior to and at approximately 30-60 min intervals during the course of the experiment. Additional recordings were made when animals showed signs of intoxication. R56865 (Janssen Pharmaceutica, Pty Ltd), a novel Ca++ antagonist, was administered at the first distinct signs of cardiac disturbances in the sheep given epoxyscillirosidin and after development of tachycardia and dyspnoea in those that received plant material. Activated charcoal was drenched at 3 g/kg to both sheep that received H. pallida about 1 h after the initial administration of R56865. All H. pallida sheep and one of the epoxyscillirosidin sheep survived. The signs of intoxication with H. pallida, namely groaning and tachypnoea, abated within minutes of treatment with R56865, but returned c. 30 min later in both animals. The treatment apparently had little effect on heart rate and EKG changes. One of the epoxyscillirosidin sheep was treated while exhibiting paroxysmal ventricular tachycardia. Although a transient improvement in conduction disturbance was recorded, the animal died soon afterwards. The results of this study indicate that the in vivo response of R56865 against induced bufadienolide cardiac disturbance in sheep is not as evident as that observed with R56865 against similar cardiac disturbance in vitro. The potential use of R56865 together with activated charcoal is discussed.
Journal of the South African Veterinary Association
The pharmacokinetics of rafoxanide administered orally at 15 mg kg-1 were compared in suckling la... more The pharmacokinetics of rafoxanide administered orally at 15 mg kg-1 were compared in suckling lambs (n = 8), aged 5-8 weeks and weaned lambs (n = 8), aged 21-22 weeks. A significant difference (p < 0.0001) in area under the curve (AUC) and maximum plasma concentrations (Cmax) were observed between the different age groups. The bioavailability, as measured by AUC and Cmax, was 2.5-3 times greater in the suckling lambs compared to the weaned lambs. No significant differences (p > 0.05) in time to maximum plasma concentrations (Tmax), distribution half-life (T1/2 alpha), elimination half-life (T1/2 beta) and mean residence time (MRT) were observed. It was concluded that the pharmacokinetic differences observed between suckling and weaned lambs may result in an increased susceptibility of suckling lambs to the toxic effects of rafoxanide. Lambs younger than 8 weeks, should preferably not be treated with rafoxanide, or the dose must be reduced.
Chronic copper poisoning was investigated in ruminants within the Phalaborwa area of the Kruger N... more Chronic copper poisoning was investigated in ruminants within the Phalaborwa area of the Kruger National Park (KNP). Exposure of ruminants to environmental copper pollution resulting form copper smelting operations of a mine in the area was examined by comparing impala faecal copper concentrations in dung heaps and tissue (liver, lung and kidney) copper concentrations of organs collected from impala and buffalo culled within three risk zones (high, moderate and low) of the study area in relation to the distance from the smelter over a period of 4 years. An additional area within the KNP not exposed to the environmental copper pollution from the mine served as control. Tissue copper accumulation was also determined in tracer impala placed in the highest risk zone. The results of this study confirmed the occurrence of chronic copper poisoning in impala and indicated an inverse relationship in extent of impala faecal copper elimination and in tissue copper accumulation in impala and buffalo with distance from the copper smelter. Impala liver copper concentrations were shown to be a reliable indicator of copper accumulation for these ruminants. The presence lung copper concentrations, indicating the exposure to airborne copper were the highest in impala culled in the zone closest to the smelter. Liver copper concentrations above the diagnostic limit of 150 ppm for chronic copper poisoning in domestic sheep were consistently found in impala within the highest risk zone. Clinical pathological measurements suggested that AST activity could possibly be used as an indicator for chronic copper poisoning in impala. It is concluded that, in addition to the environmental and geo-botanical evidence previously reported, the copper smelter of a nearby copper mine is the most likely source of copper pollution responsible for chronic copper poisoning in impala and the occurrence of high copper concentrations in buffalo in the Phalaborwa area of the KNP.
Journal of the South African Veterinary Association
Two Arabian horse stallions with behavioural problems were treated with long-acting neuroleptics ... more Two Arabian horse stallions with behavioural problems were treated with long-acting neuroleptics in order to facilitate corrective training. Perphenazine enanthate, administered intramuscularly at a dose of 0.5 mg kg-1 had an effect for 30 d. Pipothiazine palmitate (1 mg kg-1) induced tranquilization of 30 d duration as well as extra-pyramidal clinical signs, ataxia and aphagia. Neither horse showed prolapse of the penis or haemolysis.
The stability and the partitioning of closantel and rafoxanide in ruminal fluid (RF) was examined... more The stability and the partitioning of closantel and rafoxanide in ruminal fluid (RF) was examined in vitro. Stability was evaluated in two studies in a ruminal fluid-artificial saliva (RF-AS) mixture containing either drug. Drug concentrations were measured in samples collected sequentially from four batches of RF-AS fortified with either closantel or rafoxanide in one study and in four separately incubated aliquots of a RF-AS mixture of each drug in the second study at the start and at various intervals during a 24 h incubation period. The viability of the in vitro RF-AS incubation model was validated by the presence of digoxin degradation (TY> of 39,1 ± 13 h) and by the absence of significant time related differences (P > 0,5) in volume of gas produced , pH and methylene blue reduction time of the RF-AS drug mixture. Partitioning of closantel and rafoxanide was determined by measuring the relative drug concentration of the fluid and particulate phases in RF fortified with either drug at different concentrations. Closantel and rafoxanide were shown to be stable in a RF-AS mixture and were not subjected to any significant biodegradation. An initial marked reduction in drug concentration measured in the RF-AS mixture during the first 2 h of incubation was attributed to the attachment of both drugs onto particulate matter. This was subsequently confirmed in the partitioning study. More than 80 % of closantel and rafoxanide was shown to be associated with the particulate phase of RF.
Induction of chronic copper poisoning in ten boma-confined impala was attempted in a randomized, ... more Induction of chronic copper poisoning in ten boma-confined impala was attempted in a randomized, single dose, parallel designed, titration study using five increasing oral doses, ranging between 125 mg/kg to 1000 mg/kg, of copper oxide needles. Two untreated impala were kept as controls. Impala (n = 1) from each treatment group were culled 52 d and 105 d after treatment and examined for tissue copper accumulation and signs of chronic copper poisoning. Despite the high doses of copper administered to the impala and liver copper concentrations above 150 ppm WM achieved in two animals, no clinical signs related to chronic copper poisoning were observed. Faecal copper concentrations indicated that the major portion of copper oxide particles was excreted in the faeces.
Journal of the South African Veterinary Association, 1981
Six groups of 6 lambs each were treated orally with rafoxanide at dosages ranging from 0 to 37,5 ... more Six groups of 6 lambs each were treated orally with rafoxanide at dosages ranging from 0 to 37,5 mg/kg live mass in multiples of 7,5 mg/kg. The lambs were slaughtered 27 to 31 d after treatment for post mortem examination. No clinical, ophthalmological or pathological changes attributable to treatment were detected in any of the lambs. Possible differential diagnoses and predisposing factors for rafoxanide toxicity are discussed. It is suggested that plasma-rafoxanide assay be used as a diagnostic tool.
The Onderstepoort journal of veterinary research, 2000
Morphological changes associated with rumino-reticular development was compared in two groups of ... more Morphological changes associated with rumino-reticular development was compared in two groups of SA Mutton Merino lambs (n = 12) fed different diets at 3-5 weeks, 17-19 weeks and 31-33 weeks of age. Diet groups were identified as MMH or MHH according to the sequence at which the full-milk replacement (M) or hay (H) diet were fed to the lambs over the three study phases (phases I, II and III) preceding each age period. Prominent differences in the morphology (size and volume) and function (pH, proteolytic activity and microbial population) of the rumino-reticulum were observed in indicator lambs (n = 2) killed at every age period and also between milk-fed and hay-fed lambs. The size of the rumino-reticulum was rudimentary at 3-5 weeks of age and remained underdeveloped in lambs at 17-19 weeks of age which had received a full-milk replacement diet during phase II. One lamb, slaughtered at 3 weeks of age, showed a large distended rumen with severe sloughing of the surface cells of the ...
Revue scientifique et technique (International Office of Epizootics), 2009
The globalisation of trade and food, the increased volume and speed of international travel, clim... more The globalisation of trade and food, the increased volume and speed of international travel, climate change, and the related escalation of emerging and re-emerging infectious diseases mean that countries are now more interconnected and interdependent than ever before. Africa is beleaguered by a range of endemic infectious and parasitic tropical diseases which, due to its diverse wildlife populations and indigenous livestock, can serve as a reservoir of high-impact or transboundary diseases and play a role in the emergence of disease, particularly at the wildlife, domestic animal and human interfaces. It is therefore essential to integrate animal and public health issues into the veterinary curriculum. Veterinary training in most parts of sub-Saharan Africa has focused on producing veterinarians to serve the livestock sector although socio-economic changes and privatisation of Veterinary Services have caused curriculum adjustments, as have globalisation and the increased risk of the ...
Journal of the South African Veterinary Association, 2005
Peltophorum africanum (Fabaceae) is a deciduous tree widespread in southern Africa. The plant has... more Peltophorum africanum (Fabaceae) is a deciduous tree widespread in southern Africa. The plant has many ethnomedical and ethnoveterinary uses. Root and bark decoctions are used to treat diarrhoea, dysentery, sore throat, wounds, back and joint pains, HIV-AIDS, venereal diseases and infertility. Pastoralists and rural farmers use the root and bark extracts to treat diarrhoea, dysentery, infertility, and to promote well-being and resistance to diseases in cattle. To evaluate these ethnobotanical leads, dried leaves, stem bark and root bark were extracted with ethanol, acetone, dichloromethane and hexane. Polyphenols in the extract were determined by the Folin-Ciocalteu method with gallic acid as standard. Qualitative antioxidant activity was screened by spraying thin layer chromatograms (TLC) of the extracts with 0.2% 1,1-diphenyl-2-picryl hydrazyl (DPPH), and quantified with Trolox equivalent antioxidant capacity (TEAC) assay. Minimum inhibitory concentration (MIC) and total antibacte...
Journal of the South African Veterinary Association, 1995
The bioavailability of a modified rafoxanide oral suspension was compared to the original innovat... more The bioavailability of a modified rafoxanide oral suspension was compared to the original innovator product and a generic formulation in a single dose, randomised, parallel design study in sheep (n = 30). The area under the rafoxanide plasma concentration versus time curve (AUC), AUC extrapolated to infinity, and maximum plasma rafoxanide concentrations (Cmax), were used to compare the extent of absorption of the formulations. All 3 parameters were significantly (p < or = 0.01) smaller for both the modified and generic formulations relative to the original product. There were no significant (p > 0.05) differences between the modified and generic formulations. The mean point ratio % of the modified to original and modified to generic formulations for the 3 parameters were 36.4%, 35%, 45.9% and 70.9%, 70%, 79.7%, respectively. In terms of the calculated 90% confidence t-intervals of the mean % ratios, the modified and generic formulations were not bioequivalent to the original p...
Journal of the South African Veterinary Association, 1995
Specific treatment of canine babesiosis consists of antibabesial drugs and, in severely anaemic a... more Specific treatment of canine babesiosis consists of antibabesial drugs and, in severely anaemic animals, blood transfusion. Supportive therapy is also required, particularly in animals with complicated disease. Strategies for treatment of uncomplicated and complicated babesiosis are discussed. Definitive recommendations cannot be provided on the basis of available information, but suggestions are made, based on accepted therapeutic principles, pathophysiological mechanisms, therapy used in human malaria, and clinical experience. The problems of fluid therapy in complicated babesiosis, particularly in animals with oliguria, cerebral babesiosis and pulmonary oedema, are presented, with consideration given to the use of hypertonic fluids. The benefits of bicarbonate and alternative alkalinisers in life-threatening lactic acidaemia, a relatively common occurrence in complicated babesiosis, are debated, as are the benefits of oxygen therapy in anaemic hypoxia. Drug therapy and management...
Trichostrongylus colubriformis is an important cause of parasitic gastroenteritis in ruminants, w... more Trichostrongylus colubriformis is an important cause of parasitic gastroenteritis in ruminants, where it causes protracted diarrhoea, rapid loss of weight, loss of production and death. The in vitro efficacy of extracts of Peltophorum africanum was determined against this parasitic nematode. Eggs and larvae of T. colubriformis were incubated at 23°C in the extracts of the leaf, bark and root of
In the veterinary industry, long acting oxytetracycline formulations are loosely referred to as t... more In the veterinary industry, long acting oxytetracycline formulations are loosely referred to as those formulations that only require a single dose at 20 mg/kg to achieve clinical cure and to be repeated after three days only if required. Short acting oxytetracycline formulations are recommended for use once a day for four days, at a dose of 10 mg/kg IV and 10mg/kg IM on day one, 10 mg/kg IM on day two and 5 mg/kg IM on days three and four. The primary objective of this study is to demonstrate that, based on pharmacokinetics, a double dose of a conventional short acting, 135mg/ml formulation of oxytetracycline has a longer action than a single dose of the same formulation. As a secondary objective the efficacy and safety of a single, double dose of a conventional oxytetracycline formulation are compared to multiple, single doses of a conventional formulation as well against a single dose of a long-acting formulation. Factors that influence the duration of action of a parenteral oxyte...
Journal of the South African Veterinary Association, Dec 7, 1999
The halogenated salicylanilides are a large group of compounds developed mainly for their antipar... more The halogenated salicylanilides are a large group of compounds developed mainly for their antiparasitic activity in animals. Several halogenated salicylanilides with potent antiparasitic activity have been synthesised of which only closantel, niclosamide, oxyclozanide, rafoxanide and resorantel are commercially available. Closantel and rafoxanide, which represent the most important drugs in the group, are used extensively for the control of Haemonchus spp. and Fasciola spp. infestations in sheep and cattle and Oestrus ovis in sheep in many parts of the world. Niclosamide is used extensively for its anticestodal activity in a wide range of animals. Antiparasitic activity of the halogenated salicylanilides has also been demonstrated against a large number of other internal parasites, in particular haematophagous helminths, and external parasites including ticks and mites, in a variety of animal species. Several cases of toxicity and mortality have been reported for closantel and rafoxanide in sheep and goats. Their unique pharmacokinetic behaviour appears to play an important role in the efficacy and safety of these compounds. The chemical and physical characteristics, mode of action, pharmacokinetics, antiparasitic activity and toxicity of the halogenated salicylanilides in animals are reviewed.
The Onderstepoort Journal of Veterinary Research, Jun 1, 2000
Morphological changes associated with rumino-reticular development was compared in two groups of ... more Morphological changes associated with rumino-reticular development was compared in two groups of SA Mutton Merino lambs (n = 12) fed different diets at 3-5 weeks, 17-19 weeks and 31-33 weeks of age. Diet groups were identified as MMH or MHH according to the sequence at which the full-milk replacement (M) or hay (H) diet were fed to the lambs over the three study phases (phases I, II and III) preceding each age period. Prominent differences in the morphology (size and volume) and function (pH , proteolytic activity and microbial population) of the rumino-reticulum were observed in indicator lambs (n = 2) killed at every age period and also between milk-fed and hay-fed lambs. The size of the rumino-reticulum was rudimentary at 3-5 weeks of age and remained underdeveloped in lambs at 17-19 weeks of age which had received a full-milk replacement diet during phase II. One lamb, slaughtered at 3 weeks of age, showed a large distended rumen with severe sloughing of the surface cells of the stratum corneum. The size of the rumino-reticulum increased in size (2 x) in lambs which were fed hay relative to the milk-fed lambs during phase II and reached adult proportions in all lambs at 31-33 weeks of age. Ultrastructural examination showed that rumen papillae were more developed in lambs fed hay during phase II when compared to those of milk-fed lambs. Rumen papillae were best developed in phase III Iambs.
Two anaesthetized sheep were intoxicated with epoxyscillirosidin, the main cardio-active bufadien... more Two anaesthetized sheep were intoxicated with epoxyscillirosidin, the main cardio-active bufadienolide, extracted from Homeria pallida (Natal yellow tulp). The epoxyscillirosidin was injected intravenously as a bolus of 50 micrograms/kg, followed 30 min later by a continuous infusion in a normal saline drip (0.9% NaCl) at 25 micrograms/kg/h. In addition, another two conscious sheep were poisoned by intraruminal dosing of 1,25 g/kg of dried H. pallida plant material. Electrocardiograms, heart and respiratory rates and venous-acid-base levels were recorded prior to and at approximately 30-60 min intervals during the course of the experiment. Additional recordings were made when animals showed signs of intoxication. R56865 (Janssen Pharmaceutica, Pty Ltd), a novel Ca++ antagonist, was administered at the first distinct signs of cardiac disturbances in the sheep given epoxyscillirosidin and after development of tachycardia and dyspnoea in those that received plant material. Activated charcoal was drenched at 3 g/kg to both sheep that received H. pallida about 1 h after the initial administration of R56865. All H. pallida sheep and one of the epoxyscillirosidin sheep survived. The signs of intoxication with H. pallida, namely groaning and tachypnoea, abated within minutes of treatment with R56865, but returned c. 30 min later in both animals. The treatment apparently had little effect on heart rate and EKG changes. One of the epoxyscillirosidin sheep was treated while exhibiting paroxysmal ventricular tachycardia. Although a transient improvement in conduction disturbance was recorded, the animal died soon afterwards. The results of this study indicate that the in vivo response of R56865 against induced bufadienolide cardiac disturbance in sheep is not as evident as that observed with R56865 against similar cardiac disturbance in vitro. The potential use of R56865 together with activated charcoal is discussed.
Journal of the South African Veterinary Association
The pharmacokinetics of rafoxanide administered orally at 15 mg kg-1 were compared in suckling la... more The pharmacokinetics of rafoxanide administered orally at 15 mg kg-1 were compared in suckling lambs (n = 8), aged 5-8 weeks and weaned lambs (n = 8), aged 21-22 weeks. A significant difference (p &amp;amp;lt; 0.0001) in area under the curve (AUC) and maximum plasma concentrations (Cmax) were observed between the different age groups. The bioavailability, as measured by AUC and Cmax, was 2.5-3 times greater in the suckling lambs compared to the weaned lambs. No significant differences (p &amp;amp;gt; 0.05) in time to maximum plasma concentrations (Tmax), distribution half-life (T1/2 alpha), elimination half-life (T1/2 beta) and mean residence time (MRT) were observed. It was concluded that the pharmacokinetic differences observed between suckling and weaned lambs may result in an increased susceptibility of suckling lambs to the toxic effects of rafoxanide. Lambs younger than 8 weeks, should preferably not be treated with rafoxanide, or the dose must be reduced.
Chronic copper poisoning was investigated in ruminants within the Phalaborwa area of the Kruger N... more Chronic copper poisoning was investigated in ruminants within the Phalaborwa area of the Kruger National Park (KNP). Exposure of ruminants to environmental copper pollution resulting form copper smelting operations of a mine in the area was examined by comparing impala faecal copper concentrations in dung heaps and tissue (liver, lung and kidney) copper concentrations of organs collected from impala and buffalo culled within three risk zones (high, moderate and low) of the study area in relation to the distance from the smelter over a period of 4 years. An additional area within the KNP not exposed to the environmental copper pollution from the mine served as control. Tissue copper accumulation was also determined in tracer impala placed in the highest risk zone. The results of this study confirmed the occurrence of chronic copper poisoning in impala and indicated an inverse relationship in extent of impala faecal copper elimination and in tissue copper accumulation in impala and buffalo with distance from the copper smelter. Impala liver copper concentrations were shown to be a reliable indicator of copper accumulation for these ruminants. The presence lung copper concentrations, indicating the exposure to airborne copper were the highest in impala culled in the zone closest to the smelter. Liver copper concentrations above the diagnostic limit of 150 ppm for chronic copper poisoning in domestic sheep were consistently found in impala within the highest risk zone. Clinical pathological measurements suggested that AST activity could possibly be used as an indicator for chronic copper poisoning in impala. It is concluded that, in addition to the environmental and geo-botanical evidence previously reported, the copper smelter of a nearby copper mine is the most likely source of copper pollution responsible for chronic copper poisoning in impala and the occurrence of high copper concentrations in buffalo in the Phalaborwa area of the KNP.
Journal of the South African Veterinary Association
Two Arabian horse stallions with behavioural problems were treated with long-acting neuroleptics ... more Two Arabian horse stallions with behavioural problems were treated with long-acting neuroleptics in order to facilitate corrective training. Perphenazine enanthate, administered intramuscularly at a dose of 0.5 mg kg-1 had an effect for 30 d. Pipothiazine palmitate (1 mg kg-1) induced tranquilization of 30 d duration as well as extra-pyramidal clinical signs, ataxia and aphagia. Neither horse showed prolapse of the penis or haemolysis.
The stability and the partitioning of closantel and rafoxanide in ruminal fluid (RF) was examined... more The stability and the partitioning of closantel and rafoxanide in ruminal fluid (RF) was examined in vitro. Stability was evaluated in two studies in a ruminal fluid-artificial saliva (RF-AS) mixture containing either drug. Drug concentrations were measured in samples collected sequentially from four batches of RF-AS fortified with either closantel or rafoxanide in one study and in four separately incubated aliquots of a RF-AS mixture of each drug in the second study at the start and at various intervals during a 24 h incubation period. The viability of the in vitro RF-AS incubation model was validated by the presence of digoxin degradation (TY> of 39,1 ± 13 h) and by the absence of significant time related differences (P > 0,5) in volume of gas produced , pH and methylene blue reduction time of the RF-AS drug mixture. Partitioning of closantel and rafoxanide was determined by measuring the relative drug concentration of the fluid and particulate phases in RF fortified with either drug at different concentrations. Closantel and rafoxanide were shown to be stable in a RF-AS mixture and were not subjected to any significant biodegradation. An initial marked reduction in drug concentration measured in the RF-AS mixture during the first 2 h of incubation was attributed to the attachment of both drugs onto particulate matter. This was subsequently confirmed in the partitioning study. More than 80 % of closantel and rafoxanide was shown to be associated with the particulate phase of RF.
Induction of chronic copper poisoning in ten boma-confined impala was attempted in a randomized, ... more Induction of chronic copper poisoning in ten boma-confined impala was attempted in a randomized, single dose, parallel designed, titration study using five increasing oral doses, ranging between 125 mg/kg to 1000 mg/kg, of copper oxide needles. Two untreated impala were kept as controls. Impala (n = 1) from each treatment group were culled 52 d and 105 d after treatment and examined for tissue copper accumulation and signs of chronic copper poisoning. Despite the high doses of copper administered to the impala and liver copper concentrations above 150 ppm WM achieved in two animals, no clinical signs related to chronic copper poisoning were observed. Faecal copper concentrations indicated that the major portion of copper oxide particles was excreted in the faeces.
Journal of the South African Veterinary Association, 1981
Six groups of 6 lambs each were treated orally with rafoxanide at dosages ranging from 0 to 37,5 ... more Six groups of 6 lambs each were treated orally with rafoxanide at dosages ranging from 0 to 37,5 mg/kg live mass in multiples of 7,5 mg/kg. The lambs were slaughtered 27 to 31 d after treatment for post mortem examination. No clinical, ophthalmological or pathological changes attributable to treatment were detected in any of the lambs. Possible differential diagnoses and predisposing factors for rafoxanide toxicity are discussed. It is suggested that plasma-rafoxanide assay be used as a diagnostic tool.
The Onderstepoort journal of veterinary research, 2000
Morphological changes associated with rumino-reticular development was compared in two groups of ... more Morphological changes associated with rumino-reticular development was compared in two groups of SA Mutton Merino lambs (n = 12) fed different diets at 3-5 weeks, 17-19 weeks and 31-33 weeks of age. Diet groups were identified as MMH or MHH according to the sequence at which the full-milk replacement (M) or hay (H) diet were fed to the lambs over the three study phases (phases I, II and III) preceding each age period. Prominent differences in the morphology (size and volume) and function (pH, proteolytic activity and microbial population) of the rumino-reticulum were observed in indicator lambs (n = 2) killed at every age period and also between milk-fed and hay-fed lambs. The size of the rumino-reticulum was rudimentary at 3-5 weeks of age and remained underdeveloped in lambs at 17-19 weeks of age which had received a full-milk replacement diet during phase II. One lamb, slaughtered at 3 weeks of age, showed a large distended rumen with severe sloughing of the surface cells of the ...
Revue scientifique et technique (International Office of Epizootics), 2009
The globalisation of trade and food, the increased volume and speed of international travel, clim... more The globalisation of trade and food, the increased volume and speed of international travel, climate change, and the related escalation of emerging and re-emerging infectious diseases mean that countries are now more interconnected and interdependent than ever before. Africa is beleaguered by a range of endemic infectious and parasitic tropical diseases which, due to its diverse wildlife populations and indigenous livestock, can serve as a reservoir of high-impact or transboundary diseases and play a role in the emergence of disease, particularly at the wildlife, domestic animal and human interfaces. It is therefore essential to integrate animal and public health issues into the veterinary curriculum. Veterinary training in most parts of sub-Saharan Africa has focused on producing veterinarians to serve the livestock sector although socio-economic changes and privatisation of Veterinary Services have caused curriculum adjustments, as have globalisation and the increased risk of the ...
Journal of the South African Veterinary Association, 2005
Peltophorum africanum (Fabaceae) is a deciduous tree widespread in southern Africa. The plant has... more Peltophorum africanum (Fabaceae) is a deciduous tree widespread in southern Africa. The plant has many ethnomedical and ethnoveterinary uses. Root and bark decoctions are used to treat diarrhoea, dysentery, sore throat, wounds, back and joint pains, HIV-AIDS, venereal diseases and infertility. Pastoralists and rural farmers use the root and bark extracts to treat diarrhoea, dysentery, infertility, and to promote well-being and resistance to diseases in cattle. To evaluate these ethnobotanical leads, dried leaves, stem bark and root bark were extracted with ethanol, acetone, dichloromethane and hexane. Polyphenols in the extract were determined by the Folin-Ciocalteu method with gallic acid as standard. Qualitative antioxidant activity was screened by spraying thin layer chromatograms (TLC) of the extracts with 0.2% 1,1-diphenyl-2-picryl hydrazyl (DPPH), and quantified with Trolox equivalent antioxidant capacity (TEAC) assay. Minimum inhibitory concentration (MIC) and total antibacte...
Journal of the South African Veterinary Association, 1995
The bioavailability of a modified rafoxanide oral suspension was compared to the original innovat... more The bioavailability of a modified rafoxanide oral suspension was compared to the original innovator product and a generic formulation in a single dose, randomised, parallel design study in sheep (n = 30). The area under the rafoxanide plasma concentration versus time curve (AUC), AUC extrapolated to infinity, and maximum plasma rafoxanide concentrations (Cmax), were used to compare the extent of absorption of the formulations. All 3 parameters were significantly (p < or = 0.01) smaller for both the modified and generic formulations relative to the original product. There were no significant (p > 0.05) differences between the modified and generic formulations. The mean point ratio % of the modified to original and modified to generic formulations for the 3 parameters were 36.4%, 35%, 45.9% and 70.9%, 70%, 79.7%, respectively. In terms of the calculated 90% confidence t-intervals of the mean % ratios, the modified and generic formulations were not bioequivalent to the original p...
Journal of the South African Veterinary Association, 1995
Specific treatment of canine babesiosis consists of antibabesial drugs and, in severely anaemic a... more Specific treatment of canine babesiosis consists of antibabesial drugs and, in severely anaemic animals, blood transfusion. Supportive therapy is also required, particularly in animals with complicated disease. Strategies for treatment of uncomplicated and complicated babesiosis are discussed. Definitive recommendations cannot be provided on the basis of available information, but suggestions are made, based on accepted therapeutic principles, pathophysiological mechanisms, therapy used in human malaria, and clinical experience. The problems of fluid therapy in complicated babesiosis, particularly in animals with oliguria, cerebral babesiosis and pulmonary oedema, are presented, with consideration given to the use of hypertonic fluids. The benefits of bicarbonate and alternative alkalinisers in life-threatening lactic acidaemia, a relatively common occurrence in complicated babesiosis, are debated, as are the benefits of oxygen therapy in anaemic hypoxia. Drug therapy and management...
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Papers by Gerry Swan