Epidemiological studies on ovine parasitic gastroenteritis at Easter Bush

Abstract

Two flocks of Suffolk ewes with lambs and one flock of Cheviot ewes with lambs,and their four pastures were monitored for gastrointestinal nematode infestations from October 197 3 until July, 19 74.Faecal examinations included egg counting and the identification of third stage strongyle type larvae.Herbage was also examined for infective larval contamination.

It was shown that the epidemiology of ovine parasitic gastroenteritis is complex and variable even on this single farm.Only the Cheviot ewes illustrated a typical peri-parturient rise and they maintained,on average,egg counts which were fifty percent lower than the Suffolk breed.

Haemonchus contortus dominated the egg and larval counts,including the larvae from herbage.Ostertagia spp. and Trichostrongylus spp. larvae were found to be much less numerous.Haemonchus contortus was the main contributor to the peri-parturient rise.Strongyloides papillosus egg counts were high in both the lambs and the ewes during the eight weeks following lambing.

The overall pasture contamination rate was found to be surprisingly low.Parasitic findings correlated well with management practices and recent changes in the local climate.