Horak, Ivan GerardClark, R.Jansen, B.C.2016-09-272016-09-2720161964Horak, IG & Clark, R 1964, 'The pathological physiology of Ostertagia circumcincta infestation’, Onderstepoort Journal of Veterinary Research, vol. 31, no. 2, pp. 163-176.0330-2465http://hdl.handle.net/2263/57042The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentation PDF-Format.I. Trials are described in which six sheep and one goat were artificially infested with O. circumcincta and their reactions studied in detail. 2. The main pathological findings were: (i) Marked decrease in packed red cell volume, haemoglobin concentration and circulating red blood cell volume. (ii) A sharp drop in plasma inorganic phosphate which occurred in five of the seven animals. (iii) Anorexia, decreased apparent nitrogen absorption and weight loss or retarded weight gain. (iv) A decrease in plasma albumin, gamma globulin and total circulating plasma proteins. 3. Egg counts were low even with large worm burdens. 4. On reinfestation two sheep cleared themselves of the original and challenging infestation. 5. Large numbers of larvae were necessary to cause death.en©1964 ARC-Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). ©2016 University of Pretoria. Department of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle