Eficácia do fosfato de levamisol em nematódeos gastrintestinais de caprinos e ovinos

Abstract

Gastrointestinal parasitism is considered the main obstacle in the production of small ruminants and the occurrence of parasites resistant to anthelmintics has delayed their control. The aim of this study was to evaluate the sensitivity of gastrointestinal nematodes to levamisole (LEV) in sheep and goat simultaneous-raised herds. We used 28 naturally infected Boer goats and 28 Texel sheep. Both species were divided into four groups of seven animals: T1) treated with 9 mg/kg of LEV phosphate, T2) 6.75 mg/kg; T3) 4.5 mg/kg and T4) control group, not treated. The animals were evaluated for 21 days for faecal egg count per gram of feces - EPG, color of the conjunctiva with the FAMACHA method, hematocrit and body weight. In sheep, the T1 and T2 were considered highly effective (> 95%) and T3 was 86%, which is the recommended therapeutic dose for sheep. The LEV has no official indication to be used in goats and showed a decreased on the EPG by 30, 11 and 4%, 14 days after treatment, demonstrating its ineffectiveness. The correlations between the parameters evaluated in sheep, were significant (P<0.01), except FAMACHA and body weight. In the case of goats, hematocrit and FAMACHA the correlation was also not significant. The main parasite identified in stool cultures of the two species, taken before and after treatments was Haemonchus contortus (> 84%). It is concluded that the LEV was dose-dependent effective in sheep. LEV cannot be considered as an effective compound in the control of gastrointestinal parasites in goats, possibly due to changes in the drug kinetics when compared to sheep and its usage should be discouraged.