The epizootiology of nematode parasites of sheep in the Karoo

Abstract

Total and differential worm counts were carried out post mortem on sheep slaughtered at regular intervals at the Grootfontein College of Agriculture, Middelburg, Cape Province. Fourth stage larvae were recovered at every autopsy. Usually the larvae exceeded the number of adult worms in H. contortus and O. columbianum. There was a positive correlation between faecal egg counts and adult worm burdens of H. contortus and to a lesser extent O. columbianum and Trichostrongylus spp. Strategic dosing is recommended in April, September and December.