Overwinter of cattle gastrointestinal nematode in western Canada. Gastrointestinal nematode of cattle

The ability of infective larvae of cattle gastrointestinal nematode (GIN) species to overwinter on pastures in northerly climatic zones with very cold dry winters is poorly understood. This is an important knowledge gap with critical implications for parasite risk assessement and control. Parasite control practices in these regions generally do not consider the role overwintered larvae in the parasite epidemiology. We have investigated the ability of cattle GIN L3 to survive on western Canadian pastures over the winter. We have applied ITS-2 nemabiome metabarcoding as a novel approach to determine the species composition of envronmental infective L3 populations in order to determine the survival of the different GIN species. We also employed tracer calves to determine the infectivity of overwintered larvae and their ability to establish adult worm infections in the spring. Less...