Abstract

This study was conducted during May 2011 to December 2012 in Western Oromiya to determine the prevalence of gastrointestinal nematodes in naturally infected Horro sheep and associated risk factors. A total of 1680 faecal samples were examined using flotation and modified McMaster methods. Identification of all isolated nematodes was performed on larvae recovered from pooled faecal cultures and worms collected from slaughtered animals. The overall prevalence was observed to be 24.7% (95% confidence interval: 22.6 to 26.8) and majority of the infected animals (88.9%) had low faecal egg counts per gram (50 to 800). Season, grazing management, age, agro-ecology and body condition scores showed significant association (p < 0.001) with prevalence and mean nematode faecal egg counts recorded. Results revealed thatHaemonchus contortus was the most prevalent parasite detected followed byTrichostrongylus species. The Horro sheep were infected with diversified gastrointestinal nematodes that can seriously affect the health and productivity of the animals. Many animals were sub-clinically infected without attracting awareness of farmers to undertake control measures. Therefore, to improve the production potential of this indigenous breed of sheep and the livelihood of the farmers, control strategies based on the epidemiology of the parasites and production systems should be implemented.

Key words: Horro sheep, gastrointestinal nematodes, epidemiology, prevalence, Oromiya, Ethiopia.