02211naa a2200277 a 450000100080000000500110000800800410001910000230006024500890008326000090017252014600018165000150164165000150165665000100167165000100168165000170169165000100170865300140171865300180173270000130175070000240176370000250178770000160181270000230182877300820185119568992024-07-12       2000    bl uuuu     u00u1 u    #d1 aOLIVEIRA, C. M. B.  aEfficacy of doramectin in the treatment of sheep naturally infested by Oestrus ovis.  c2000  aAbstract: This study was conducted to evaluate the efficacy of a single intramuscular injection of doramectin at a dose rate of 200 or 300 µg/kg against natural infestations of the nasal bot fly, Oestrus ovis. Forty-eight corriedale sheep naturally infested by O. ovis were randomly allocated to 4 treatment groups (T1, T2, T3 and Control) of 12 animals each. On day 0, the animals of the control group were necropsied and the developmental stages of O. ovis larvae present in the nasal cavities and sinuses were identified and counted. Also on day 0, the animals of T1, T2, and T3 groups received saline solution (1 ml/50 kg body weight) and doramectin at 200 and 300 µg/kg, respectively. All treatments were administered by deep intramuscular injection on the left hindleg. The animals were necropsied 14 days after treatment and the developmental stages of O. ovis larvae were identified and counted. The results showed that a single intramuscular injection of doramectin at either 200 or 300 µg/kg was 100% effective against all developmental stages of O. ovis larvae (first, second and third instar). Compared to the non-medicated control group (T1), the efficacy of doramectin at 200 or 300 µg/kg was highly significant (P&lt0.0001). The efficacy of the treatment was confirmed by the fact that two weeks after treatment, there was a substantial recovery from the sinusitis. No adverse reaction to doramectin was observed in the treated animals.  aDoramectin  aLarvicides  aSheep  aLarva  aOestrus ovis  aOvino  aLarvicida  aNasal bot fly1 aMORO, E.1 aCAPRONI JÚNIOR, L.1 aGONÇALVES, L. C. B.1 aUMEHARA, O.1 aOLIVEIRA, L. O. de  tRevista Brasileira de Parasitologia Veterináriagv. 9, n. 1, p. 61-64, 2000.