Identification of cross-resistance and multiple resistance in Eimeria tenella field isolates to commonly used anticoccidials in Pakistan

A battery trial was conducted to evaluate the drug sensitivity in Eimeria tenella field isolates against the commonly used anticoccidials salinomycin (60 ppm), maduramicin (5 ppm), and clopidol (125 ppm) in broiler chicks. These anticoccidials were mixed in feed at d 12 of age, and inoculation was given on d 14 of age. Drug sensitivity was determined by using the global index, which is composed of percentage weight gain, FCR, lesion score, oocyst index, and mortality percentage. In the present study, all the E. tenella isolates showed partial resistance against salinomycin, whereas varying degrees of sensitivity were observed against maduramicin and clopidol.