Ostertagia spp. in Lambs and Pregnant Ewes

Abstract

It was confirmed that lambs born in the Central Tabelands area of New South Wales became infested with Ostertagia spp. to a potentially pathogenic level very early in their lives. By studying the faecal egg output of ewes in this area it was shown that a marked Ostertagia spp. egg count rise occurred in all lambing ewes at or closely associated with parturition. It was also shown that it was not likely that these ewes had themselves picked up many Ostertagia spp. larvae during the latter part of their pregnancy and that the parturient egg count rise mainly resulted from larvae ingested prior to, or early in, pregnancy.