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Journal of the South African Veterinary Association

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Volume 71, Issue 1, March 2000

Workshops propose National Programme for Veterinary Helminthology for South Africa : information
Vatta, A.F.Krecek, R.C.Du Plessis, A.Havemann, A.R.Van der Merwe, J.S.
2-5

Abstract: A workshop was held at Onderstepoort on 2-3 July 1999 to set priorities in veterinary helminthology for South Africa. Representatives from 19 organisations attended. The workshop achieved 2 of its 3 aims, namely to identify the priority areas within the field and to set specific objectives to be achieved in addressing these needs. Seven strategies were proposed, namely, motivation, education, therapeutic, wormresistance, animal tolerance, biological control and diagnostic strategies. Afollow-up session took place on 8 September 1999 and at this workshop and in subsequent meetings, preliminary action plans were developed for these strategies. It was felt that the proposed activities delineated by this process should formthe basis for a National Programme for Veterinary Helminthology and a national forum is to be convened to encourage all stakeholders to consider, discuss and adopt these activities. The forum is scheduled to take place in April 2000.

A krimpsiekte-like syndrome in small stock poisoned by Ornithogalum toxicarium Archer & Archer : article
Botha, C.J.Schultz, R.A.Van der Lugt, J.J.Archer, C.
6-9

Abstract: Krimpsiekte (the syndrome associated with chronic cardiac glycoside poisoning) was purportedly induced by Ornithogalum toxicarium in the Karas mountains area of Keetmanshoop, Namibia. This chinkerinchee species was previously linked to a condition known as `kwylbek' krimpsiekte in small stock in the Beaufort West district of the Western Cape Province, South Africa. In a dosing trial, respiratory distress, tachycardia and sternal recumbency were observed in 2 sheep drenched with fresh plant material. A fluorescence polarisation immunoassay (FPIA) detected the presence of a substance that cross-reacted with digoxin antibodies in some of the plant material collected at Keetmanshoop and Beaufort West. This is the first time that apparent cardiac glycoside poisoning was induced by a southern African chinkerinchee species. The presence of the cardiac glycoside-like substance in O. toxicarium requires further chemical verification.

The prevalence of bovine viral diarrhoea antibodies in selected South African dairy herds, and control of the disease : article
Ferreira, G.M.Lourens, D.C.Van Vuuren, M.
10-13

Abstract: The prevalence of bovine viral diarrhoea (BVD) serologically positive animals in 18 dairy herds with clinical and pathological lesions suggestive of BVD infection, the post-vaccinal seroconversion rates in negative animals vaccinated twice with an inactivated BVD vaccine, and the control measures taken, are described. The pathological and histopathological findings in 6 necropsies performed on animals that died in 5 separate herds closely resembled published descriptions. Positive immunohistochemistry results in 3 cases confirmed the diagnosis in those animals. In 1 herd the prevalence of prevaccinal BVDantibodies was only 36.8 %, while the prevalence varied from 79.85 to 100 % in the remainder. Control measures taken included immunoprophylaxis with an inactivated vaccine, culling animals that were serologically negative after vaccination that were regarded as probably persistently infected (PI) and the implementation of additional biosecurity measures. The prevalence of serologically negative PI animals in 10 herds varied from 0.38 to 4.04 %, with 8 herds less than 1 %and 2 herds at 2.79 %and 4.04 %, respectively. Methods based on vaccinating the herd, followed by serological testing and culling cattle that did not develop an antibody titre, are not reliable. The identification of PI animals should be confirmed by isolation of the virus or identification of the antigen.

Blood pressure changes in dogs with babesiosis : article
Jacobson, L.S.Lobetti, R.G.Vaughan-Scott, T.
14-20

Abstract: Systemic arterial blood pressures were measured in 30 dogs with acute babesiosis, 10 each with mild uncomplicated, severe uncomplicated and complicated disease. Ten healthy dogs were used as controls. Hypotension was defined as more than 3 standard deviations below the control mean. Normal mean pressures (±SD) were: systolic arterial pressure 151 (±11) mm Hg, diastolic arterial pressure 89 (±8) mm Hg and mean arterial pressure 107 (±10) mmHg. Hypotension was the most frequent abnormality, and increased strikingly in incidence as disease severity increased, with 5/10 dogs in the complicated group being hypotensive for systolic, diastolic and mean arterial pressures, compared with 2/10 in the severe uncomplicated group and 0/10 in the mild uncomplicated group. Systolic, diastolic and mean arterial pressures in the complicated group and severe uncomplicated group, and systolic pressure in the mild uncomplicated group, were significantly lower than in the controls. There were no significant relationships between arterial pressures and age, pulse rate, respiratory rate, temperature, mucous membrane colour or haematocrit. There was a significant negative correlation between arterial pressures and white cell and immature neutrophil counts. Arterial pressures differed significantly between dogs that were clinically collapsed and those that were not, but not between survivors and non-survivors. Pulse pressure (systolic - diastolic) was low in 7/10 complicated, 1/10 mild uncomplicated, and 1/10 severe uncomplicated cases, and differed significantly between the complicated and control groups. The high incidence of hypotension in clinically severe babesiosis has important implications for therapy.

Babesia bovis and B. bigemina DNA detected in cattle and ticks from Zimbabwe by polymerase chain reaction : article
Smeenk, I.Kelly, P.J.Wray, K.Musuka, G.Trees, A.J.Jongejan, F.
21-24

Abstract: From blood collected from 94 cattle at 12 locations in the eastern and northeastern areas of Zimbabwe, DNA was extracted and analysed by polymerase chain reaction with primers previously reported to be specific for Babesia bigemina and Babesia bovis. Overall, DNA of Babesia bigemina was detected in the blood of 33/94 (35 %) cattle and DNA from B. bovis was detected in 27/58 (47 %) of cattle. The prevalence of DNA of B. bigemina was significantly higher in young animals (<2 years) (23/46) than in animals over 2 years of age (10/48; (chi)2 = 8.77; P < 0.01 %). Although tick sampling was not thorough, Boophilus decoloratus could be collected at 7/9 sites sampled and Boophilus microplus at 4/9 sites. Of the 20 B. decoloratus allowed to oviposit before PCR analysis, 1 (5 %) contained DNA that could be amplified with primers for B. bigemina while 12 (60 %) were positive with primers for B. bovis. Of the B. microplus allowed to oviposit, 11/16 (69 %) were positive for B. bovis DNAby PCR and 2/16 (12 %) were positive for B. bigemina.

The prevalence of subclinical mastitis in dairy goats in Kenya : article
Ndegwa, E.N.Mulei, C.M.Munyua, J.M.
25-27

Abstract: California mastitis test (CMT), direct leukocytes counts and bacteriological examination were performed on 630 milk samples from apparently healthy mammary glands of dairy goats comprising a mixed population of German Alpine, Toggenberg, Saanen and Galla crosses to find the prevalence of subclinical mastitis. The prevalence of subclinical mastitis was 9.8 %according to CMT, 9.7 %according to direct leukocyte counts and 28.7 %by bacterial isolation during a 3-month period. The proportion of the bacteriologically positive milk samples was significantly (P < 0.01) higher than that positive for CMTand direct leukocyte counts. There was a significant (P < 0.01) correlation between CMT and direct leukocyte counts. There was no significant direct relationship between bacterial isolation and CMT. Bacterial organisms were isolated in 22.5 % of the 568 CMT-negative milk samples. The results suggest that bacterial organisms isolated from the CMT-negative milk samples were either latent infections or did not stimulate any significant increase in somatic cell counts that could be detected by either the CMT or direct leukocyte counts. The observations of this study indicate that the mere presence of bacteria in goat's milk does not mean that the udder is infected and so does not warrant antibiotic therapy.

Flystrike prevention on Merino lambs with the insect growth regulator dicyclanil : article
Schmid, H.R.Hyman, W.B.De Bruin, C.Van Zyl, A.P.Junquera, P.
28-30

Abstract: The efficacy of a ready-to-use 5 %dicyclanil pour-on formulation as a preventative of natural flystrike on Merino lambs was investigated in a field trial involving 5 sites in the southern Cape Province. A total of 1804 lambs treated with dicyclanil were compared with 882 untreated control lambs for up to 25 weeks after treatment. Efficacy was assessed by calculating the weekly cumulative strike rate at each site and aggregated for all sites, as well as by calculating the percentage reduction achieved in treated lambs. Cumulative strike rates for the untreated controls aggregated for all sites at Weeks 9, 14 and 19 after treatment reached 6.2, 12.8 and 17.8 %, respectively, compared with 0.4, 1.7 and 3.6 %for the dicyclanil treated lambs. Percentage control aggregated for all sites at Weeks 9, 14 and 19 after treatment was 93, 87 and 80 %, respectively. Heavy rains during the 1st half of the trial did not substantially reduce the efficacy of the product.

Effects of anthelmintic treatment and feed supplementation on grazing Tuli weaner steers naturally infected with gastrointestinal nematodes : article
Magaya, A.Mukaratirwa, S.Willingham, A.L.Kyvsgaard, N.Thamsborg, S.
31-37

Abstract: A study was carried out to determine the epidemiology of gastrointestinal nematodes in indigenous Tuli cattle and the effect of dietary protein supplementation and anthelmintic treatment on productivity in young growing cattle. Forty steers with an average age of 18 months were divided into 4 groups; 1) fenbendazole (slow release bolus) and cottonseed meal (FCSM group), 2) fenbendazole (FBZ group), 3) cottonseed meal (CSM group) and 4) control (no cottonseed meal and no fenbendazole) (control group). Performance parameters measured included wormeggs per gram of faeces (EPG), packed cell volume (PCV), albumin and live-weight gain. Results showed that faecal worm egg counts were lower and PCV was higher in the FCSM and FBZ groups than in the CSM and control groups (P < 0.01). Weight gains were higher in the CSMand FCSM groups than in the FBZ and control groups (P < 0.05). The cost benefits of anthelmintic treatment and dietary supplementation were apparent in this study. The improved growth performance of the FCSM, FBZ and CSM groups reflected a financial gain over the controls on termination of the study. The dominant genera of gastrointestinal nematodes on faecal culture, pasture larval counts and necropsy were Cooperia and Haemonchus. The incidences of Trichostrongylus, Oesophagostomum and Bunostomum were low.

A preliminary study on the serum protein response in canine babesiosis : research communication
Lobetti, R.G.Mohr, A.J.Dippenaar, T.Myburgh, E.
38-42

Abstract: Total serum protein, albumin, globulin, globulin fractions (alpha, beta and gamma globulins) and an acute-phase protein ((alpha)1-acid glycoprotein) were evaluated in dogs with naturally occurring mild (Group 1), severe (Group 2) or complicated babesiosis (Group 3). Results showed that the total serumprotein, albumin, A/G ratio and (alpha)globulins were statistically different between Groups 1 and 2. There was no statistical difference between groups with total, (beta)and (gamma) globulins. The findings from this study suggest that dogs with mild and severe babesiosis had low total serum proteins, albumin, A/G ratio and (alpha) globulins; dogs with complicated babesiosis showed no typical serum protein changes or patterns; and that there was no evidence of an acute-phase response detectable on serum protein electrophoresis in any of the 3 groups. A marked acute-phase response was, however, present, as measured by the (alpha)1-acid glycoprotein, in all 3 groups. As this was a retrospective study, the possibility that the observed responses were due in part to concurrent disease could not be excluded.

Survey of the incidence, diagnosis, clinical manifestations and treatment of Spirocerca lupi in South Africa : research communication
Lobetti, R.G.
43-46

Abstract: A questionnaire survey of 716 veterinary practices was undertaken to determine the incidence of Spirocerca lupi in dogs in South Africa. In total, 49 %of the questionnaires were returned, indicating a possible incidence of 28 %. Fewer than 4 cases per year were recorded by 82 %of the respondents; 4-12 by 14 %; 12-24 by 3 %; and more than 48 by only 1 %. No seasonal incidence was reported by 48 %of the respondents. Large breeds were considered to be at greater risk by 43 % of respondents. No specific age or sex was identified to be at higher risk. The most common complaints by owners and clinical findings were vomition (46 %), weight loss (27 %), coughing (21 %) or regurgitation (20 %), although 14 %of respondents reported no abnormal clinical findings. Diagnostic methods used were radiology (74 %), endoscopy (27 %), post mortem examination (34 %) and faecal flotation (4 %). Complications associated with S. lupi were reported by 76 % of respondents, which included oesophageal neoplasia (41 %), hypertrophic osteopathy (38 %) and acute haemothorax (30 %). Specific treatments were used by 58 % of the respondents, whereas 42 % of the respondents either used no treatment (72 %) or recommended euthanasia (28 %). Of the treatment group, 52 % used ivermectin, 27 % doramectin, 13 % other deworming drugs (benzimidazoles, nitroscanate), and 8 % used disophenol. Sixty-three percent of the respondents considered their treatment ineffective, whereas 31 % considered it effective, and 6 % were unsure. The overall mortality rate was high.

Prognostic indicators of post partum viability of kids born to Escherichia coli-vaccinated or unvaccinated does : research communication
Munyua, S.J.M.Karioki, D.I.Chibeu, D.M.Wabacha, J.K.Thaiya, A.G.Njenga, J.M.Gathuma, J.M.

Mitaru, B. 47-52

Abstract: This study was undertaken to determine some blood and other physiological parameters with potential for use as prognostic indicators of viability of newborn goat kids. Of the 143 kids born during the on-farmstudy, 97 were crosses of Galla _ Small East African (SEA) and 46 were pure SEA. The SEA _ Galla kids were 46 single males, with a mean body weight at birth of 2.77 ± 0.22 kg , 43 females with a mean body weight at birth of 2.36 ± 0.76 kg and 5 and 3 sets of female and male twins (mean body weight at birth of 1.8 ± 0.19 kg and 2.05 ± 0.07 kg for the female and male kids, respectively). The SEA kids comprised 36 single male and female kids (mean body weight at birth of 2.48 ± 0.04 kg and 10 sets of twins (both male and female) (mean body weight at birth of 1.50 ± 0.04 kg ). Pre-suckling sera obtained on-station from kids born of does vaccinated against Escherichia coli (n = 8) and unvaccinated does (n = 7) had a total protein content of < 40.0 g/l and no detectable levels of IgG and A or E. coli antibodies. Sera obtained 12 hours post partum from kids that survived in both groups contained about 19-22 g of Ig g/ , 50-80 g total protein/ , blood glucose of >5 mmol/l and had an E. coli antibody titre of between 1/160 and 1/640. On the other hand, kids that died within 48 hours of birth (parturient deaths) and had been classified in categories 3 and 4 righting reaction had low (< 40 g//l ) total protein, low white blood cell count (4000/m/l ) and low blood glucose concentration (< 4.9 mmol//l ). It is concluded that kids with delayed righting reaction (> 45 minutes), low rectal temperature (< 36 șC), low birth weights (< 1.5 kg for singles and < 1.0 kg for twins), low white blood cells (< 4000/ m/l ), low (< 2 mmol/l ) blood glucose levels, low total protein (< 40.0 g//l ), low (< 1:160) E. coli antibody titre and IgG ( < 3350 mg//l ) in sera obtained 12 hours after birth have a poor prognosis for survival.

Screening of five drugs for efficacy against Babesia felis in experimentally infected cats : research communication
Penzhorn, B.L.Lewis, B.D.Lopez-Rebollar, L.M.Swan, G.E.
53-57

Abstract: The efficacy of 5 drugs was tested against experimental Babesia felis infection in domestic cats. Two of the drugs, rifampicin and a sulphadiazine-trimethoprim combination, appeared to have an anti-parasitic effect, but were inferior to primaquine. The other 3 drugs, buparvaquone, enrofloxacin and danofloxacin, had no significant anti-babesial effect.

Capture and immobilisation of aardvark (Orycteropus afer) using different drug combinations : research communication
Nel, P.J.Taylor, A.Meltzer, D.G.A.Haupt, M.A.
58-63

Abstract: Nine aardvarks (Orycteropus afer) were captured in the southern Free State, South Africa, for the placement of abdominal radio transmitters. Five combinations of ketamine hydrochloride with xylazine hydrochloride, midazolam or medetomidine hydrochloride were used to induce anaesthesia. In some cases the level of anaesthesia was maintained with 1.5 % halothane. A mixture of ketamine hydrochloride and medetomidine hydrochloride was found to be most effective. Atipamizole reversed the affects of medetomidine hydrochloride, resulting in a smooth and full recovery within 8 minutes. The immobilisation and subsequent anaesthesia of these animals on cold winter nights resulted in hypothermia, and keeping the animals warm was essential to the success of the procedures undertaken. Reversal of the sedative medetomidine hydrochloride proved to be important, because animals that were released before they were fully conscious took refuge in their burrows so that care was impossible.

Hypoxaemia and suspected pulmonary oedema in a Dorper ewe after diazepam-ketamine induction of anaesthesia : short communication
Stegmann, G.F.
64-65

Abstract: Anaesthesia was required in an 18-month-old Dorper ewe scheduled for surgical repair of an abdominal hernia. Anaesthesia was induced with diazepam (0.15 mg/kg) and ketamine (6 mg/kg), and maintained with halothane in oxygen on a circle anaesthetic machine. Hypotension, hypoxaemia, cyanosis and pulmonary oedema were observed from the start of surgery, but the symptoms improved towards the completion of the procedure. The aetiology of this condition could not be established. It is suggested that propylene glycol, the organic solvent in the diazepam formulation, may have stimulated the release of vasoactive substances that resulted in pulmonary oedema.