Effect of Haemonchus contortus burdens on productivity of sheep in a semi-arid environment

Abstract

The effects of a moderate burden of Haemonchus contortus on liveweight change, milk production, lamb growth and wool growth were studied in groups of 60 lactating ewes and their lambs, 20 dry ewes which had lost their lambs and 100 weaners. Half of the ewes and weaners were infected with 2000 H. contortus larvae; the other half were treated with anthelmintic, 10 ml levamisole. The treatments of ewes were undertaken 1 week prior to the commencement of lambing, and the weaners were also treated at that time. On day 37 after treatment faecal samples were collected for parasite egg counts, all animals including lambs were weighed and milk yield was measured in lactating ewes after oxytocin injection. Midside samples were taken for wool growth measurement on day 87. Lambs were weighed 140 days after treatment to calculate growth rate.