NR 28. Dual implantation use and breed types effect on bulls under savanna conditions

Abstract

Seventy bulls were used with average initial weigth of 365 kg and average age of 26 mo in order to evaluate the use of the dual anabolic implantation and the effect of the breed types on growth in savannas. The treatments were randomly assigned T1: Non implant; T2: Trenbolone acetate (ATB)+ 17b-estradiol implanted; T3: Zeranol plus ATB+17b-estradiol implanted. The breed types were Bos indicus predominance (PI) and Bos taurus (PT). The trial lasted 120 d. An analysis of variance-covariance, using the covariable (initial weigth]. Implant and breed types did not influence (P>.05) on average daily gain during the finishing phase. However, T2 was 4 % heavier than T3 and Bos taurus more heavier than Bos indicus. In conclusion, the use of dual implantation in crossbred animals are not recommend.