PSII-B-19 - Adaptation Periods Protocol for Nellore Cattle in Intensive Pasture Finishing

Abstract: Our objective was to evaluate the performance of Nellore cattle in intensive pasture finishing (TIP), fed for 96 days and submitted to different adaptation periods, aiming to reach 2% of BW of DMI concentrate (DMIc)/BW at the end of the adaptation period. A total of 240 Nellore bulls (iBW 359kg±5.02 kg; 20 mo) were distributed in randomized blocks, allocated in paddocks of 2.4 ha (Urochloa brizantha cv. Xaraés; 10 animals/paddock), with two treatments with 12 replications (paddock as experimental unit). The treatments were: 1) 9 days on adaptation (ADAP9), 2% DMIc/BW on the 10^th day; 2) 14 days on adaptation (ADAP14), 2% DMIc/BW on the 15^th day. The animals were weighed fasting (± 16h) at the beginning, on day 28, and at the end of the experimental period, the DMIc was measured daily by the difference between offered and leftovers. Data were analyzed using the SAS ANOVA procedure at P< 0.05. Evaluating the period between the beginning and the 27^th day, ADAP9 showed greater DMIc (6.9 vs. 6.5kg/d; P=0.009), greater DMIc/BW (1.8 vs. 1.7% BW; P =0.0043) and greater fluctuation in DMIc (9.4 vs. 5.9% DMIc/d; P< 0.001) compared with ADAP14. In the total fattening period, there was no difference between treatments (P >0.05), for DMIc (8.7 vs. 8.5 kg DM/d), DMIc/BW (2 vs. 2% BW), fluctuation in DMIc (4.91 vs. 4.31% DMIr/d), days to reach target (17 vs 20 d), ADG (1.3 vs. 1.3 kg/d), ADG/DMIc (0.127 vs. 0.128), fBW (483 vs. 484kg) and HCW (285 vs. 285kg). The use of an adaptation period of less than 14 days did not improve performance, and therefore would not be recommended.