Estratégias de suplementação para antecipação da idade à puberdade para novilhas de corte em pastagem tropical

Abstract

This paper aimed to evaluate the supplements formulated from different sources of protein during the rainy season over the productive performance of beef heifers during breeding. In order to evaluate productive performance, 20 Holstein x Zebu crossbred heifers, with average body weight of 234 kg and approximate age of 14 months, were divided into five paddocks of B. decumbens Stapf of 2.5 ha each, in a completely randomized design with five treatments and four repetitions. The supplements were based on soybean meal (FS); cottonseed meal (FA) 38% crude protein (CP) (FA 38); corn gluten meal 60% CP (GM) and wheat bran + urea (FTU); and a treatment witness, composed of mineral mix (MM) only. The daily amount of supplement was established for providing about 180 g of CP day-1 ; that is, 0.450, 0.550, 0.350 and 0.450 kg animal-1 day-1 , respectivelly, for the treatments with FS, FA38, GM and FTU. The animals were weighted every 28 days and rotated among the paddocks every 7 days. The ones which were submitted to the FTU treatment showed higher average daily gains (ADG) (p < 0.10) than those which received a MM treatment (0.839 X 0.666 kg day-1 ). The 500 g supply of supplement containing urea, FTU and minerals for heifers during breeding is recommended when intending to get moderate weight gain - around 850 g day-1