Lungworm
Lungworm infestation is caused by exposure of grazing animals to nematode (roundworm) larvae on pasture. The lifecycle of the lungworm is about 4 weeks long i.e. from the ingestion of larvae to the excretion of infective larvae by the affected animal. In the worst case, within four weeks of ingesting lungworm larvae, the cow or calf can be shedding literally millions of fresh larvae onto the pasture