Epidemiology of Nematodirus battus infection in eastern Scotland

A field investigation was carried out from 1981 to 1983 on the prevalence of Nematodirus battus under different systems of lowland sheep management. Pasture larval counts, ewe and lamb worm egg counts, and tracer lamb worm counts were carried out. As expected, contamination was generally greater on permanent pasture than on new leys as measured by pasture larval counts and lamb worm egg counts. However significant contamination was also recorded on young grass fields for which alternate grazing with young calves may have been partly responsible. It is suggested that the 1983 hatch was delayed because of a drop in soil temperature in late March which may have increased subsequent scour problems involving N battus seen in May.