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 that Haemonchus contortus was the most prevalent parasite detected
followed by Trichostrongylus species. The Horro sheep were infected with diversified gastrointestinal
nematodes that can seriously affect the health and productivity of the animals. Many animals were subclinically 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.
