Clinical evaluation of anaemia in sheep: early trials

Show simple item record Malan, F.S. Wessels, C.D.
dc.contributor.editor Boomker, Jacob Diederik Frederik
dc.contributor.upauthor Van Wyk, J.A. (Jan Aucamp) 2012-04-16T10:28:25Z 2012-04-16T10:28:25Z 2012 2001
dc.description The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format. en
dc.description.abstract Trials were conducted on a farm in Mpumalanga Province in South Africa to test the possibility of grading the colour of the ocular mucous membranes of sheep as an indication of the extent to which the animals are affected by Haemonchus contortus infection. The range of observed colour shades were classified into five categories, from red, through red-pink, pink and pink-white to white. Over a period of 125 days routine drenching of a flock of 388 sheep on irrigated kikuyu ( Pennisetum clandestinum) pasture was terminated. During this time the animals were examined at practically weekly intervals and haematocrit determinations done for all the sheep with pale conjunctivae. Only those sheep having a haematocrit of 15% or lower were treated. Compared to a previous drenching tempo of close to every 3 weeks during the Haemonchus season on the farm, drenching was reduced by approximately 90%, as 70% of the sheep did not require salvage drenching and only 10% of the flock had to be given more than one salvage treatment. At the time of the trial the five clinical classifications were not related to predetermined haematocrit categories. However, when compared to categories that were set in later trials, 94% of the clinical estimates in the present trial were either in the correct haematocrit category, or, if not, the sheep were probably not disadvantaged by the errors. In 2.6% of cases the incorrect estimate may have placed the sheep concerned in jeopardy, as the haematocrit values were so low that salvage drenching was required, while the sheep were not regarded as anaemic. Changes in the mean haematocrit values of drenched and undrenched sheep were mirrored reciprocally by the changes in clinical colour estimates. Lactating ewes were by far the most susceptible class of sheep, as only 44.6% of them were able to manage without drenching, compared to 83% of dry, and 70.6% of pregnant ewes. Correlations between the haematocrits and clinical estimates were highly significant, although the associations were not high enough to give reasonable surety that the haematocrit values of individual animals could be predicted with confidence from their clinical classifications. Exceptionally large numbers of worms were recovered from seven of the 14 sheep that were culled because of age at the end of the trial, but these were reflected neither in their faecal worm egg counts, nor, with one exception only, in clinical signs. en
dc.description.librarian mn2012 en
dc.identifier.citation Malan, FS, Van Wyk, JA & Wessels, CD 2001, 'Clinical evaluation of anaemia in sheep: early trials’. Onderstepoort Journal of Veterinary Research, vol. 68, no. 3, pp. 165-174. en_US
dc.identifier.issn 0030-2465
dc.language en
dc.publisher Published jointly by the Agricultural Research Council, ARC-Onderstepoort Veterinary Institute and the Faculty of Veterinary Science, University of Pretoria. en
dc.rights © ARC-Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). © University of Pretoria. Dept of Library Services (digital). en
dc.subject Veterinary medicine en
dc.subject Anaemia en
dc.subject Haematocrit en
dc.subject Haemonchus contortus infection en
dc.subject Irrigated pasture en
dc.subject Sheep en
dc.subject.lcsh Veterinary medicine -- South Africa
dc.subject.lcsh Hookworm disease -- South Africa en
dc.subject.lcsh Sheep -- Diseases -- South Africa en
dc.title Clinical evaluation of anaemia in sheep: early trials en
dc.type Article en

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