Endoparasite prevalences of the highland sheep in Ethiopia

Abstract

The status of gastrointestinal parasites of sheep in the Ethiopian highlands was studied in 1988 and 1989 at five sites about 300 km apart. Nematode log eggs per gram (epg) counts varied from 0.7 to 0.8 and 0.3 to 0.5 for natural and stubble-grazed sheep, respectively. The worm counts from the abomasum and intestines of 122 necropsied sheep at Debre Berhan and Tulu Meko were low to moderate with Trichostrongylus colubriformis dominating in the count. The worm counts were highest at Tulu Meko. Few Haemonchus contortus worms were recovered from the abomasum and low counts of Fasciola hepatica were obtained from the liver of necropsied sheep. Monthly prevalences of positive nematode eggs varied from 12.6 to 49.3% and 7.1 to 50.7% for pasture-grazing and stubble-grazing sheep, respectively, with significant ( P<0.05) differences between groups within the month. While age prevalences of positive nematode eggs were significantly ( P<0.05) different in most months, sex prevalences differed only in 4 months. The least-squares means (±SE) of positive nematode log epg varied from 1.87 (±0.02) to 2.35 (±0.03) and 1.77 (±0.05) to 2.25 (±0.02) for natural and stubble-grazing groups, respectively. Naturally-grazed sheep had significantly ( P<0.05) higher positive nematode log epg than stubble-grazed sheep in most months. Monthly prevalences of positive trematode epg varied from 1.0 to 60.8% and 0.2 to 43.5% for the natural and stubble-grazing sheep, respectively, with significant ( P<0.05) differences between the two groups within the month. Certain monthly age and sex prevalences were also significantly ( P<0.05) different within months in both natural and stubble-grazing sheep. In the necropsied sheep, the seasonal prevalences of Dictyocaulus filaria and Trichostrongylus colubriformis were 66.7–100.0% and 64.0–100.0%, respectively. Trichostrongylus axei, H. contortus, Oesophagostomum columbianum, Bunostomum trigonocephalum and Trichuris skrjabini had low prevalences.