Field Trials Comparing Salinomycin (Coxistac) , Monensin, and Lasalocid in the Control of Coccidiosis in Broilers

Abstract

Salinomycin a broad spectrum ionophore anticoccidial, was evaluated for toleration and efficacy at 60 ppm in the feed of broiler reared to market weight under floor pen conditions. Approximately 13,500 broilers of three different breeds were used in 5 trials, two conducted in Maine and one each in Georgia, North Carolina, and Texas. The related ionophore anticoccidials, monensin and lasalocid, were included for comparison at 100 and 75 ppm respectively. Coccidial exposure was provided by used litter. In addition, 1 to 2 cycles of seeder birds were used in Texas and North Carolina. Five chicks/pen were necropsied at about 3 weeks of age to determine the extent of coccidial infection and to ascertain the lesion control provided by the anticoccidials. Five birds/pen were also necropsied at trial termination to check for untoward drug effects. Coccidiosis was not detected in the Georgia and North Carolina trials, but mild infections occurred in Texas and in one Maine trial. A moderate outbreak occurred in the second trial conducted in Maine. Salinomycin and monensin had equivalent lesion control which was statistically superior (P<.05) to lasalocid. In 4 of 5 trials, monension had the poorest weight gain while lasalocid had the best; however, salinomycin and lasalocid could be differentiated from each other by this criteria in only 2 of the 5 trials. In one trial, the weight gain of all medicated treatments were statistically equivalent. There was no coccidiosis related mortality among medicated treatments, nor were there any differences in feed conversions among any of the treatments. Untoward drug effects were not observed at termination necropsy.