Changes

''O. ostertagi'' have a direct, non-migratory life-cycle. Calves are infected following ingestion of L3 that under moist conditions migrate from the faeces to pasture. The larvae are swallowed, pass through the forestomachs and develop in the abomasal gastric glands to the L4 stage, emerging as adult (L5) worms after nearly 3 weeks. Adult female worms then produce strongyle eggs which are passed out with the faeces. The prepatent period is 16 - 23 days (5-6 months if arrested at early (E)L4 stage).

''O. ostertagi'' have a direct, non-migratory life-cycle. Calves are infected following ingestion of L3 that under moist conditions migrate from the faeces to pasture. The larvae are swallowed, pass through the forestomachs and develop in the abomasal gastric glands to the L4 stage, emerging as adult (L5) worms after nearly 3 weeks. Adult female worms then produce strongyle eggs which are passed out with the faeces. The prepatent period is 16 - 23 days (5-6 months if arrested at early (E)L4 stage).

== Epidemiology and Pathogenesis==

==== Epidemiology and Pathogenesis====

The epidemiology of ''O.ostertagi'' is complex due to the hardyness of the eggs in the environment and the ability of larvae to hyperbiose. Clinical infections of this worm are termed [[Ostertagiosis - Cattle|Ostertagiosis]], the clinical page explains the pathophysiology and the epidemiology of the disease.

The epidemiology of ''O.ostertagi'' is complex due to the hardyness of the eggs in the environment and the ability of larvae to hyperbiose. Clinical infections of this worm are termed [[Ostertagiosis - Cattle|Ostertagiosis]], the clinical page explains the pathophysiology and the epidemiology of the disease.