Aim: This study was conducted to determine the prevalence of gastrointestinal (GI) worms in Wonosobo and thin-tailed sheep from the slope of Mount Sumbing.

Materials and Methods: Fecal samples (n=305) were collected directly from the rectum of Wonosobo and thin-tailed sheep during the dry and rainy seasons in Wonosobo Regency, Central Java Province, Indonesia. The presence of GI helminth eggs in the fecal samples was assessed using the modified McMaster egg counting technique. The identification of the eggs or oocysts was done on the basis of their morphology and size.

Results: The highest prevalence of GI worms was observed in male thin-tailed sheep (76.47%) during the rainy season, whereas the lowest prevalence was observed in female Wonosobo sheep (47.36%) during the dry season. The types of GI nematodes observed in these two types of sheep were Haemonchus contortus, Ostertagia spp., Trichostrongylus spp., Bunostomum spp., Trichuris spp., and Moniezia spp. The GI worms with the highest prevalence were of Haemonchus spp. and were observed in male thin-tailed sheep. The prevalences of the two types of sheep assessed at an altitude of 1150 m above sea level were higher than those observed at the altitude of 1586 m. The prevalence of clinical and sub-clinical parasites infestation in Wonosobo and thin-tailed sheep in Kwadungan village was significantly different (p<0.05).

Conclusion: This study showed that two types of local sheep on the slope of Mount Sumbing are infected with various GI worms during the dry and rainy seasons. The highest prevalence of GI worms was found in thin-tailed sheep at an altitude of 1150 m above sea level during the rainy season, with H. contortus being the most prevalent GI parasites.

Keywords: gastrointestinal, nematodes, prevalence, sheep, Wonosobo sheep.