Study on abomasal nematodes of sheep and goats: Comparison and characterization of vulvar morphology of Haemonchus in Hawassa, Ethiopia

Abstract

The study was conducted from November 2011 to April 2012. Two hundred twenty two sheep and 174 goats’ abomasum were examined according to the standard procedures. The overall prevalence of abomasal nematode was 82% for sheep and 76.4% for goats. The parasitic species specific prevalence was 80.6, 25.7, and 14.8% for Haemonchus species, Trichostrongylus axei and Teladorsagia circumcincta, respectively in sheep and 75.2, 9.8, 14.2% in goats. Sex related prevalence for sheep was 79.6, 25.7, 17.1% in male and 81.9, 25.5, and 11.7% in female for Haemonchus species, Trichostrongylus axei and Teladorsagia circumcinecta respectively. The sex related prevalence in goats was 71.9, 5.7, 6.1% and 81.6, 21.6, 16.6% for Haemonchus species, Trichostrongylus axei and Teladorsagia circumcinecta, respectively for male and female. The overall mean worm count was 7459.4 for sheep and 6244.9 for goats. The sex related mean worm burden was significantly higher (P<0.05) in female than male for both sheep and goats. Female Haemonchus species Vulvar morphology was characterized and linguiform vulvar morphology was the most and knobbed type vulva morphology was the least frequently identified vulvar type both from sheep and goats’ worms with higher proportions of linguiform vulva from goats than sheep. It was concluded that the variation in prevalence and vulvar morphotype was almost similar with little deviations between sheep and goats. So importance of role of sheep to goats or goats to sheep as reservoir should be assessed. Investigations using advanced molecular techniques should be carried on genetic diversity and pathogenecity of Haemonchus in special as drug resistance is another emerging challenge in addition to the economic loss. Key words: Abomasal nematodes, Haemonchus, Hawassa, prevalence, vulvar morphology.