Type 2 ostertagiosis.

Ostertagia ostertagi is the most important gastro-intestinal nematode affecting cattle in the UK. It has the potential to cause disease (ostertagiosis) in young grazing animals, usually in the second half of the year (type 1 disease) and also to inhibit its development in the host and cause disease in late winter/early spring (type 2 disease). Type 2 disease may have a low morbidity but is more severe than type 1 disease, possibly due to the mass synchronous emergence of inhibited parasites causing severe abomasal damage and also possibly due to failure to diagnose and treat quickly. This parasite continues to interest researchers due to the overwhelming evidence of it causing significant economic loss in cattle. [ABSTRACT FROM AUTHOR]