Bagaço de cana-de-açúcar como volumoso exclusivo para novilhas leiteiras

Abstract

The objective of this study was to evaluate the effect of different concentrate levels (40, 50, 60, and 70%) on intake, digestibility of nutrients, and performance of heifers fed sugarcane bagasse as exclusive roughage. In addition, establish a proportion of concentrate: roughage suitable for rearing phase and anticipation of first calving. Twenty Girolando heifers with an average body weight of 198.3 ± 25.6 kg were assigned in a randomized block design, established according to body weight were used. The experiment lasted 114 days, with 30-days to adaptation of diets and management and 84-days to data collection and samples, as well as animal performance evaluations. Except for NDFap intake that has not changed (P>0.05) with increasing concentrate levels, there was a linear increase (P<0.01) of the intake of dry matter (DM), organic matter (OM), crude protein (CP), and digestible organic matter (DOM). The apparent digestibility of DM and OM showed a quadratic behavior (P<0.05), with maximum values of 65.3 and 68.9% in the levels of 58 and 56% concentrate inclusion, respectively. The apparent digestibility of CP linearly reduced (P<0.01), while the NDFap (P>0.05) was not influenced by increasing concentrate levels. The final weight (237.6 to 299.4 kg/d) (P<0.01), daily weight gain (0.5 to 1.2 kg/d) (P<0.01), total weight gain (35.2 to 83.6 kg/d) (P<0.01), final withers height (117.2 to 120.8 cm) (P<0.05), final rump height (121.4 to 124.8 cm) (P<0.05), final thoracic perimeter (140.2 to 152.2 cm) (P<0.001), and final body length (125.0 to 130.8 cm) (P<0.01) linearly increased with the concentrate levels. There was a high correlation between morphometric measurements and the average weight of animals. It is recommended to use sugarcane bagasse and concentrated in the proportions50:50 in the heifer’s diets, for occurrence of first calving at 24 months.