A field study of some nematode parasites of bovines in a semi-arid area, with special reference to their biology and possible methods of prophylaxis

Preliminary field investigations revealed the presence of Cooperia pectinata, C. punctata, Haemonchus placei, Oesophagostomum radiatum and Bunostomum phlebotomum as the most common parasites of bovines in the North Western Cape. Experiments on the ecology and epizootology of these parasites were carried out under field conditions, at the Armoedsvlakte Research Station near Vryburg in the North Western Cape. Possible methods of prophylaxis based on experimental observations are described, and the possible use of strategic drenching, using anthelminthics which gave promising results, is included.The 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 the final presentation PDF-format

Studies on Haemonchus contortus. I. The influence of previous exposure to Trichostrongylus axei on infestation with H. contortus

A group of Merino sheep, aged 6-7 months was infested orally with 50 000 infective larvae of Trichostrongylus axei. This group and a control group were challenged 90-92 days later with 50 000 infective larvae of Haemonchus contorus. Previous infestation with T. axei caused a reduction of more than 80% in the worm burdens of H. contorus in more than 80% of the sheep.The 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 the final presentation PDF-format

An anthelmintic test for gastro-intestinal nematodes of cattle

Suitable experimental groups of calves for controlled anthelmintic tests were created by repeatedly dosing susceptible worm-free animals orally with infective larvae of Haemonchus placei, Ostertagia ostertagi, Oesophagostomum radiatum and Cooperia spp. (C. pectinata plus C. punctata) and giving a single percutaneous dose of Bunostomum phlebotomum. Calves were infested in such a way that at treatment the worms were either present as third stage larvae, fourth stage larvae or fifth and adult stages. Enough calves were infested to enable the data to be interpreted by the non-parametric method. Optimal results were achieved by testing compounds against a specific stage of development. A combined test was evolved where two groups of 11 calves were treated when the worms were at different stages of development but only a single group of 9 control calves was used. For more accurate worm counts delaying the slaughter of calves for 3 to 4 weeks after administering the final dose of infective larvae is advocated. Nylon grit gauze with 500 micron apertures allows worms to migrate more easily into the filtrate of the ingesta than nylon mesh with 225 micron apertures in which they tend to become trapped.The 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 the final presentation PDF-format

Overberg Research Projects. IV. The development of resistance to Nematodirus in lambs and spontaneous cure of Teladorsagia in weaners

Soon after 12-week old suckling lambs reached a peak infestation of Nematodirus resistance developed, worm burdens falling by 43,1-97,5% in 18 week and 11-month old sheep respectively. Both Teladorsagia (syn. Ostertagia) and Trichostrongylus reached a peak geometric mean (G) of 18 099 and 3 278 worms on 02 December 1987 in weaners 5-6 months old. Within 6 weeks--6 months of sheep grazing on safe pastures, spontaneous cure of Teladorsagia occurred, worm burdens falling by 77,3-98,7 % but not of Trichostrongylus which was only reduced by 34-40%.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

Overberg Research Project. IX. First stage larvae per gram (L₁p.g.) of faeces : an efficient method of diagnosing nematode parasites of sheep ante mortem

Nematode eggs were collected by mixing the faeces with a sugar solution, filling a flat-sided medicine bottle (100 ml), and allowing eggs to float and adhere to the upper surface for 30 min. After discarding the faeces, eggs hatched within 24 h at 20-30⁰C. Each genus was counted in a counting chamber and the L₁p.g. estimated. The morphology of L₁ of Haemonchus, Teladorsagia, Trichostrongylus, Oesophagostomum and Strongyloides is briefly described.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

An anthelmintic test for larval stages of sheep nematodes

A test for the evaluation of anthelmintics against the larval stages of nematodes is described. Worm-free lambs are given doses of infective larvae of several species of nematode in such a way as to ensure that all the developmental Stages are present on the day of treatment. The drug under test is administered by intraruminal injection on day 0 and controls are slaughtered on day 0 or day 1 and day 3 to ascertain the numbers of worms present at the time of dosing. The treated sheep are killed from days 1 to 3 after dosing. The worms are recovered by Shone's water bath method and counted. Details are given of all the techniques used in the test.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on Paramphistomiasis. II. The mass production of metacercariae of Paramphistomum microbothrium Fischoeder 1901

1. Methods of collecting paramphistome eggs, largely freed of faeces, and their hatching are described. 2. Young B. tropicus were readily infested with paramphistomes: only 12.4 per cent of adult snails were infested. 3. Two methods of infestation are described. 4. The mass production, collection and counting of metacercariae are described. 5. After exposure to a 40 watt yellow electric light bulb at 1½ inches above the water surface 98.6 per cent of cercariae were shed within five hours.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Recovery of parasitic nematodes from the gastro-intestinal tract of a mule at autopsy

An autopsy was carried out on an aged mule and the gastro-intestinal nematodes recovered in a modified Baermann apparatus in a waterbath. Ingesta were initially placed on fibreglass gauze (apertures 1,5 X 1,1 mm) and the filtrate subsequently poured on to a double gauze platform in traps. The upper platform had nylon grit gauze with an aperture of 700 micron, while the lower platform had gauze with an aperture of 500 micron. As many as 56,7% Probstmayria vivipara and 75,2% of the other nematodes migrated through all three layers of gauze into the filtrate, which constituted less than 5% of the total ingesta. Although 12,9% of the strongyles were washed off the caeco-colonic wall, none were recovered when this gut wall was subsequently digested.The 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 the final presentation PDF-format

Studies on paramphistomiasis. I. The propagation of Bulinus tropicus Krauss 1848

1. A system for the mass propagation of B. tropicus in shallow water aquaria 1s described. 2. A system of maintaining numbers of small shallow water aquaria suitable for varied experimental purposes is outlined. 3. Both systems are inexpensive and characterized by simplicity of dc5ign, construction and maintenance.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Overberg Research Projects. X. Faecal egg counts in the interpretation of nematode worm burdens in sheep

Worm egg counts were compared with nematode worm burdens from data collected from >400 sheep killed in experiments on the epidemiology of nematode parasites in the Overberg, in the winter rainfall area of the southern Cape Province. Data were analysed in several ways but no method could be found to accurately estimate the number of nematodes present from the faecal egg count in respect of individual sheep. However, the mean natural log egg count (epg) can roughly predict the mean natural log nematode count in groups of sheep.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201