Field studies on the seasonal incidence of Nematodirus battus and N. filicollis in sheep

Abstract

1. The seasonal incidence of Nematodirus infection in sheep was followed by faecal egg counts, post-mortem examination and pasture larval studies.2. It was shown that only one generation of adult worms was produced each year and that the life history required a prolonged resting stage on the pasture, which took 12 months to complete.3. The influence of this type of life cycle on the parasitic disease caused by Nematodirus, and on its control, are discussed.