Feedlot performance, feeding behavior, carcass and rumen morphometrics characteristics of Nellore cattle submitted to strategic diets prior the adaptation period

Abstract The study was designed to evaluate the effects of either nutritional restriction or intake of concentrate feedstuffs before beginning the adaptation period on days to adapt, feedlot performance, feeding behavior, carcass characteristics, rumen and cecum morphometric of Nellore cattle. The experiment was designed as a completely randomized block, replicated 8 times (4 animals/pen), in which 96 Nellore bulls with an initial body weight (BW) of 365.52 ± 39.19 kg were fed in 24 pens according to the treatments, as follows: Restriction (Tifton hay fed at 1.4% of BW + mineral supplement); Control (Tifton hay fed ad libitum + mineral supplement) and Concentrate (Tifton hay fed ad libitum + 0.5% of BW of a mix of concentrate feedstuffs and mineral supplement). This study lasted 144-d, divided into 2 periods, as follows: 32-d of preadaptation, in which cattle were submitted to the treatments previously described, and 112-d of finishing period, where all cattle were fed the same diets. At the end of preadaptation period, one animal per pen was slaughtered (n = 24) for carcass, cecum and rumen evaluations, and the remaining 72 animals were harvested after 112-d of finishing period. No significant (P > 0.10) treatment effect was observed for days to adapt to the high-concentrate diet, which was 14 days (SEM: 0.63). Cattle submitted to restriction had greater (P