Sheep Infection by Haemonchus Species: Effect on Haematocrit and Evaluation of the FAMACHA Method in Arsi Negele District, Oromia, Ethiopia

摘要

Infection with Haemonchus species in sheep at Arsi-Negele district was determined by differential third-stage larvae and the objective was to evaluate the validation of FAMACHA chart in the diagnosis of Haemonchus infection. The animal's anemia level was determined by using the FAMACHA method and their corresponding PCV (packed cell volume) were determined by haematocrit centrifugation method. The color of the ocular membrane of all animals was scored 1 to 5 using the FAMACHA card and blood samples were collected from each animal for determination of PCV. Fecal samples also collected from sampled animals tested for fecal egg counts (FEC), and fecal culture for identification of third stage larvae of Haemonchus species. All sheep studied were negative for Fasciola and were not heavily infested by lice and ticks. A highly significant negative correlations [(R-square = 0.28, Coef. = -0.78); (R-square= 0.58, Coef= -0.34)] was observed between Haemonchus larvae and PCV, and PCV and eye color respectively. Positive correlations [(R-square= 0.19, Coef. = 1.53); (Rsquare= 0.274, Coef = 0.05)] was observed between FAMACHA score and Haemonchus infection, and FAMACHA score and egg per gram of faces (EPG) respectively. The PCV of the Haemonchus positive sheep had a strong negative correlation with the EPG (R-square=0.53, Coef= -0.023). We evaluated the validity of FAMACHA eye scoring to measure severely infested sheep and got strong correlation among FAMACHA eye scoring, PCV and Fecal culture positivity. As a conclusion the FAMACHA anaemia scoring guide can be used to treat only severely anemic sheep and hence reduce mass treatment and this reduce chance of drug resistance.