Inactivation of eggs and larvae of the cattle nematodes Ostertagia ostertagi and Cooperia oncophora after passage in pigs

The study investigated the effect of gastrointestinal passage in pigs on fr ee-living stages of bovine nematodes. Two Landrace x Yorkshire pigs, A and B, were fed fresh eggs of Ostertagia ostertagi and Cooperia oncophora while two other pigs, C and D, were fed third stage larvae (D) of the same paras ites. Faeces from the pigs were collected for 48 h after ingestion. In pigs A and B, 15 and 66% of the eggs were recovered after passage, respectively . However, only 0.003 and 0.002% of the ingested eggs developed into third stage larvae (D) after subsequent culturing. In pigs C and D, 0.01 and 0.02 % of the L3 survived the passage of the gastrointestinal tract. Fresh O. os tertagi and C oncophora eggs were cultured in parasite free porcine and bov ine faeces. Only 0.05% L3 developed in porcine faeces, whereas 21% of the e ggs developed into L3 in the bovine culture. Our results demonstrate an ext remely poor rate of development and survival of both bovine nematode eggs a nd infective larvae after passage in pigs. It may imply that pigs can play an important role in reducing transmission of cattle nematodes if the two s pecies are grazed together or alternately. (C) 2001 Elsevier Science B.V. A ll rights reserved.