Effect of Zeranol in oil solution on feedlot performance of Pelibuey lambs

Abstract

Traditionally, the application of Zeranol in ruminants is carries out with implants in pellets; nevertheless its presentation in oily suspension would  facilitate its application. The work was carried out from February to May of 2004 in Yucatan, Mexico. The effect of the Zeranol in oily solution (Z-olea)
was evaluated on the daily weight gain, voluntary feed intake, and feed efficiency in Pelibuey feedlot lambs. Thirty two Pelibuey lambs were used, with a weight average of 19.8 ± 2.7 kg and 146 days of age, allotted randomly to the two treatments (T1 = no application of Z and T2 = with application), the lambs received a unique subcutaneous dose of 12 mg of Z-olea; each lamb was considered an independent experimental unit. The lambs were lodged separately, with free feed access for 56 days. Statistical differences were not observed between treatments in any variables (P > 0.05). The lambs had a daily weight gain of 323 ± 51 and 331 ± 38 g day^-1; voluntary feed intake of 1.575 ± 0.203 and 1.644 ± 0.193 kg dry matter day^-1 and feed efficiency of 4.9 ± 0.4 and 5.0 ± 0.6 for T1 and T2, respectively. Under the conditions in which this work was performed, the results indicated that Zeranol injected in oily solution, did not affect the daily weight gain, voluntary feed intake and feed efficiency in Pelibuey feedlot lambs.