Haemonchus contortus is one of the most important parasites of ruminants with worldwide distribution that can bring huge economic losses to the breeding industry of cattle, sheep, and goats. In recent 20 years, studies on H. contortus in China mainly focused on the epidemiology, population genetics, anthelmintic resistance, structural and functional studies of important genes regulating the dev...

The infective stage of Haemonchus contortus, the third-stage larva, retains the secondstage larval cuticle. Exsheathment takes place in the rumen of the host (Somerville, 1954), under the influence of a number of factors, chiefly unionized carbonic acid and dissolved gaseous carbon dioxide (Rogers, 1960). The ensheathed larva survives desiccation, but, if caused to exsheathe by appropriate trea...

A recently established Eragrostis curvula pasture 1,1 ha in size at Hennops River in the Transvaal Highveld was contaminated from 6 October 1976 until 20 May 1977 by 30 weaned Merinos, each infested with 7 000 infective larvae of H. contortus. On 2 November 1976 3 groups of weaned Merinos and again on 10 January 1977 a further group of Merinos were infested with 40 000 infective larvae of Trich...

REINECKE, R. K. An anthelmintic test for gastro-intestinal nematodes of cattle. Onderstepoort]. vet. Res. 39(3), 153-178 (1972). 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, Osterta,~ia ostertagi, Oesophagostomum radiatttm and Cooperia spp. (C. pectinata...

Dioxapyrrolomycin, pyrrolomycin C, pyrrolomycin D, and piericidin C2 produced by UC 11065 were evaluated as anthelmintics. Assays used to examine these compounds included effects on the free-living nematode Caenorhabditis elegans, ability to clear target nematodes (Haemonchus contortus and Trichostrongylus colubriformis) from jirds, and clearance of Haemonchus contortus from lambs. A crude extr...

Haemonchus contortus appears to be the most economically important helminth parasite for small ruminant production in many regions of the world. The two sheep breeds native to the Canary Islands display distinctly different resistant phenotypes under both natural and experimental infections. Canaria Hair Breed (CHB) tends to have significantly lower worm burden and delayed and reduced egg produ...

Ivermectin (IVE), one of the most important anthelmintics, is often used in the treatment of haemonchosis in ruminants. The objective of our work was (1) to find and identify phase I and II metabolites of IVE formed by the Barber's pole worm (Haemonchus contortus), and (2) to compare IVE metabolites in helminths with IVE biotransformation in sheep (Ovis aries) as host species. Ultrahigh-perform...

Haemonchus, Trichostrongylus, Ostertagia and Nematodirus worm populations of Angora goats, based on differential egg counts, are considered in relation to climatological and topographical data. Egg counts indicated that the estimated worm populations in goats that experienced wet circumstances were higher than those exposed to dry conditions. Wetness was assessed by relating spring, summer, and...

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 20-30 degrees C. Each genus was counted in a counting chamber and the L1p.g. estimated. The morphology of L1 of Haemonchus, Teladorsagia, Trichostron...

The cumulative total helminth parasite burdens of ranch calves during their first seven months of life on the North-eastern Mountain Grassland of South Africa were determined during two consecutive years. Trichostrongylus axei was the most abundant nematode parasite followed by Cooperia spp. and Ostertagia ostertagi. Haemonchus spp. occurred in relatively low numbers and its development was sig...