occurrence of anthelmintic resistant nematodes on sheep farms in england and goat farms in england and wales.a survey in 1992 showed that 44 per cent of the sheep farms tested in the south west and 15 per cent of those in the north east of england had parasitic nematode worm burdens which were resistant to benzimidazole anthelmintics, and that 65 per cent of the non-dairy goat farms tested in england and wales had resistant worms. ostertagia circumcincta was the main species in sheep and haemonchus contortus in goats. the resistance to benzimidazoles was diagnosed by a combination of an egg hatch assay ...19968843638
field observations on the control of ovine parasitic gastroenteritis in south-east england.three worm control strategies, on a commercial farm in south east england, were monitored parasitologically for a grazing season. three peaks of larval infection in june, late august and late october/early november occurred on paddocks grazed by dosed ewes and lambs on a new ley (preventive strategy). lambs dosed and moved on to a hay aftermath in july (evasive strategy), had a mean egg count of 2090 by late august, attributable to infection with haemonchus contortus. three weekly drenching of l ...19883188346
field observations on the epidemiology of abomasal parasites in young sheep during winter and spring.a flock of spring born lambs was continuously exposed to natural parasite infection from birth until selected for slaughter in groups of two or three, at monthly intervals throughout winter and spring for abomasal worm counts. meteorological data were recorded and regular estimates of infective pasture larval availability were made. parasite population changes and inhibition patterns for ostertagia spp, haemonchus contortus and trichostrongylus axei were recorded. ostertagia spp were found to su ...1979262603
the vulval flap formula of haemonchus contortus from sheep in south-east england. 19666008304
prevalence of anthelmintic resistant nematodes in sheep in south-east england.the prevalence of anthelmintic resistant nematodes among 52 commercial flocks in south-east england was investigated by comparing the faecal egg counts of groups of lambs before, and seven days after, treatment with thiabendazole and levamisole. evidence of thiabendazole resistance was found on seven farms. in each case haemonchus contortus was the only species of nematode involved. in vitro egg hatch assays carried out for isolates from these farms gave ed50 estimates of 0.065 to 0.332 microgra ...19846464318
a survey of the trichostrongylid nematode species present on uk sheep farms and associated anthelmintic control practices.a survey of sheep farms from across the uk was conducted to establish information on farming practices, the trichostrongylid nematode species present and anthelmintic usage. questionnaires and faecal samples were returned from 118 farms. first stage larvae (l(1)) were cultured from faecal samples and used for pcr analysis to determine the presence/absence of selected trichostrongylid species. teladorsagia circumcincta was the only species present on 100% of farms. haemonchus contortus was found ...201222560313
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