Prevalence, Species Composition and Worm Burden of Abomasal Nematodes of Small Ruminants Slaughtered in Hawassa, Southern Ethiopia
The study was carried out to estimate the prevalence, species composition and worm burden of abomasal nematodes of small ruminants (sheep and goats) slaughtered in Hawassa, southern Ethiopia from November 2007 through March 2008. During this period, visceral organs (abomasums) were collected from 237 animals (125 sheep and 112 goats) slaughtered in restaurants located in Hawassa. Of these, 224 small ruminants were male and the remaining 13 were females. All the carcasses examined were from adult animals. Out of the 237 organs examined, the majority (196) were collected during the dry season and the rest were collected during the wet season. Worm recovery, species identification and determination of worm burden were carried out according to standard procedures. The results showed that the overall prevalence of abomasal nematode infections in sheep and goats was 90.4% and 77.7%, respectively. Haemonchus contortus and Trichostrongylus axei were the only worms recovered in the abomasum of the slaughtered sheep and goats. In sheep, the prevalence of H. contortus and T. axei was 80% and 79.2%, respectively. In the goats, the prevalence of H. contortus and T. axei was 67.7% and 62.6%, respectively. Significant differences (P>0.05) in prevalence were not found between sex of animal, months and seasons. However, there was significant difference (P0.05) in the monthly mean worm counts between animal species and sex. In general, the findings of this study showed high prevalence and worm burden of H. contortus and T. axei which could potentially be among the most important nematodes affecting the productivity of small ruminants in the area. Further, molecular epidemiology and immunological studies are recommended to understand the transmission dynamics of these parasites and their larval ecology including associated factors.