EFFECT OF SEMDURAMICIN, SALINOMYCIN, AND MONENSIN ON PERFORMANCE, SHANK PIGMENTATION, AND COCCIDIAL LESIONS IN BROILER-CHICKENS IN FLOOR PENS

The effects of 25 ppm semduramicin, 66 ppm salinomycin, 110 ppm monens in, and unmedicated treatments on performance, shank pigmentation, and coccidial lesion scores in broiler chickens were evaluated in two flo orpen trials in the United States. On day 24 of each test, birds in ea ch treatment were inoculated via the feed with a mixture of recent fie ld isolates of Eimeria spp. at a dose rate calculated to provide 2 X 1 0(5) E. acervulina, 3 x 10(4) E. maxima, and 2 x 10(4) E. tenella spor ulated oocysts per bird. Weight gain and feed conversion were signific antly (P less than or equal to 0.05) improved in the semduramicin-trea ted broilers in comparison with the monensin-treated and unmedicated b roilers. These performance variables for the salinomycin-treated birds were intermediate between the semduramicin- and monensin-treated bird s. Shank pigmentation scores were significantly (P less than or equal to 0.05) improved in the three anticoccidial treatments compared with unmedicated birds, with the highest scores (P less than or equal to 0. 05) occurring in the semduramicin-treated broilers. Semduramicin was m ore efficacious (P less than or equal to 0.05) than salinomycin in con trolling upper intestinal lesions and more efficacious than monensin i n controlling mid-intestinal lesions. All three drugs were comparable in controlling lesions in the ceca.