Studies on the Inhibition of Development of Ostertagia spp. in Lambs

Abstract

Inhibition of development in the larvae of Ostertagia spp. infecting tracer lambs under field conditions shows a seasonal pattern (Connan, 1968) somewhat similar to that seen in O. ostertagi infections in calves (Anderson, Armour, Jennings, Ritchie and Urquhart, 1965). This finding also agrees with the seasonal appearance of dormant larvae in ewes (Soulsby, 1966; Connan, 1968) and one year old sheep (Parnell, 1962; James and Johnstone, 1967).