CIVETAN   23983
CENTRO DE INVESTIGACION VETERINARIA DE TANDIL
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Use of eprinomectin against Rhipicephalus (Boophilus) microplus in cattle: Relatinship between plasma and tick drug concentrations.
Autor/es:
LIFSCHITZ, A.; NAVA, S.; MANGOLD, A.; IMPERIALE, F.; BALLENT, M.; CANEVARI, J.; LANUSSE, C.
Lugar:
Liverpool
Reunión:
Congreso; 25th International Conference of the World Association for the Adavancement of Veterinary Parasitology; 2015
Resumen:
Eprinomectin (EPM) is a macrocyclic lactone used against endo-ectoparasites without withdrawal time in milk and meat after its pour-on administration at 0.5 mg/kg. The current work study the relationship between the plasma and the tick concentrations of EPM as well as the efficacy of EPM against Rhipicephalus (Boophilus) microplus after its administration at two different dose rates. Eighteen Braford cattle naturally infected with R. (B.) microplus were divided in three experimental groups with a similar level of infestation (Kruskal-Wallis test, P > 0.05): control group and treated groups with EPM pour-on (1 and 1.5 mg/kg). Samples of blood and tick with different stage life were taken between 0 and 21 days post-administration to measure EPM concentrations by HPLC. Female ticks (4,5-8 mm) on the cattle were counted between 1 and 21 days post-treatment to evaluate the efficacy of EPM. Plasma concentrations of EPM (have) showed a linear relationship related to the level of dose rate administered. The peak plasma concentrations were in a range between 13.8 and 90 ng/ml that guarantee the milk drug concentrations below the maximum residues level. High concentrations of EPM were detected in ticks. EPM concentrations in R. (B.) microplus reflected the plasma concentrations from the hour 30 post-treatment (r 0.84; P 0.0002). The EPM efficacy calculated with the Henderson-Tilton formula (equation?) was 92.9 % and 98.9 % (21 days post-administration) after EPM treatment at 1 and 1.5 mg/kg, respectively. The use of EPM to tick control, particularly in dairy cattle, may be a valid pharmacological tool.