Efeitos do zeranol no desempenho de bovinos e bubalinos terminados em confinamento

The present paper was carried out with data from a private farm at Tiete city, state of So Paulo, utilizing 40 steers (13 Nelore, 11 Indubrasil and 16 crossed of Holstein, brown Suiss, Charolais and Gir breeds). With 29 months of age and 14 water buffaloes males of Murrah, Jaffarabadi and Mediterraneun breeds, with 16 months age. All 11 animals received three implants of zeranol under the ear they were put in a feedlot during 120 days. They were fed in the morning and in the afternoon with retions composed by 51.4% of com silage, 0.3% of urea, 39.4% of grinded sugar cane, 17% of ground com grain, 1.8% of cotton seed meal, 5.1% of chicken litter and 0.3% of mineral salt. Statistical analysis with a complete randon design showed a highly significant effect of zeranol implant (P ≤ 0.01) for average daily gain. Water buffaloes were superior than Nelore breed by Tukey test at same level of probability. Average daily for vvater buffaloes, indubrasil, crossed and Nelore breeds were 1.151; 1.040; 849 and 704 g, respectively, and average body weights at slaughter, in the same order were 440.42, 473.18, 461.87 and 416.23 kg.