Factors influencing uptake of nematode larvae in adult dairy cattle during the grazing season and sources of pasture contamination.
Investigations on nine well managed English dairy farms showed that 85.2 per cent of 460 adult cows harboured patent nematode infections, although the worm burdens, as judged by faecal egg counts, were small. Infection took place primarily by the ingestion of grass previously contaminated either directly with bovine faeces or indirectly with slurry. Calves did not appear to contribute to the infectivity of land grazed by adults on these farms. The parasitic challenge to which cows were exposed was dependent upon the feeding regime, grassland management and the season of the year. Generally the intake of infective larvae ranged from 0 to 1500 per day but daily intakes of up to 4520 were recorded.
D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000502:physiology; D002418:Cattle Diseases / Q000469:parasitology* / Q000635:transmission; D004435:Eating; D005260:Female; D007774:Lactation; D009349:Nematode Infections / Q000469:parasitology / Q000635:transmission / Q000662:veterinary*; D006109:Poaceae / Q000469:parasitology; D011247:Pregnancy; D012621:Seasons