Transmission of Oesophagostomum spp among sows at pasture
Rose, J.H.; Small, A.J.
Veterinary Record 107(10): 223-225
1980
ISSN/ISBN: 0042-4900 PMID: 7445335 Document Number: 155798
Studies on a commercial pig farm in southern England from March 1978 to December 1979 showed that sows on pastureland excreted eggs continuously, with no marked fluctuations and an average output of around 1000 epg. Oesophagostomum spp. predominated. In 1978, infective larvae were first recovered from the herbage at the end of May but this was in one paddock only; in 4 paddocks no larvae were recovered until August when a sharp rise in pasture larval infestation occurred, followed by a drop to a moderate level which persisted until the paddocks were ploughed up at the end of October. On a 2nd area of land small numbers of larvae persisted from November 1978 to February 1979. Then none was recovered until a sharp rise occurred in mid-August, followed by a drop to a lower level. The numbers of worms (predominantly O. dentatum) in 37 sows culled at intervals throughout the study rarely exceeded a few thousand, but some sows harboured many immature worms (as many as 267 000 in one sow in February). The presence of large immature parasite populations at times when there are few larvae on pasture may be attributable to inhibited development. The anthelmintic treatment used on the farm had only a transitory effect on the parasitic infections. It is suggested that sows be treated at the end of October or later with an anthelmintic effective against adults and the larval stages.