Avaliação de indicadores de metabolismo e do comportamento ingestivo em novilhas Nelore e Guzerá, submetidas a dois planos alimentares

Abstract

The use of titanium dioxide (TiO2) and NANOLIPE® indicators was evaluated to estimate dry matter intake, fecal production and fecal recovery rate. The kinetics of the solid phase with the use of sweetened silage and the ingestive behavior of heifers kept in confinement, submitted to two feeding planes, were evaluated. Twelve heifers were used, six of the Nellore breed and six of the Guzera breed and two diets: in the first (restricted) stage, the diet was formulated to maintain live weight, allowing gains of 200 g / day and in the second phase (ad libitum), the diet was formulated to gain one kilogram / day. The statistical design was completely randomized. In the restricted period the indicators underestimated the value of consumption (P = 0.0001), being lower value was obtained by TiO2. The values for faecal production were 0.637; 0.578; 0.499 kg DM, respectively for total collection, NANOLIPE® and TiO2 (P = 0.0001). The recovery rate of the NANOLIPE® indicator was 93.37% and the TiO2 68.30% (P = 0.0001) in the restricted phase. For the kinetics of the solid phase both in the restricted phase and in the ad libitum phase there was no difference between races regarding particle kinetics (P> 0.05). The dry matter digestibility of heifers in the restricted stage was 721.14 and 690.34 g / kg DM, respectively for Guzera and Nellore (P <0.05). The ingestive behavior in the restricted phase was different only in the feed efficiency of the dry matter (DMFE) (33.32 and 18.32 g / min, for Guzera and Nellore) and in the feed efficiency of neutral detergent fiber (13.89 and 7.64 g / min, for Guzera and Nellore) (P <0.05). In the ad libitum phase the values for consumption were 8.38; 7.56; 7.50 kg DM, respectively for TiO2, actual consumption and NANOLIPE® (P <0.05). The fecal production value estimated by TiO2 was higher than that of total collection and NANOLIPE® (P <0.05). The digestibility values of DM were 674.01 and 673.23 g / kg DM, respectively for Guzera and Nellore (P> 0.05). The Guzera group presented superiority (P <0.05) in relation to the Nellore animals in the DMFE (49.48 and 26.44 g / min, respectively, for Guzera and Nellore) and NDFcp FE (18.65 and 9.97 g / min, respectively for Guzera and Nellore). It is concluded that NANOLIPE® improved the fecal production and consumption values in the ad libitum phase. TiO2 overestimated the value of consumption and fecal production in the ad libitum phase. The variables studied for particle kinetics were similar in the Guzera and Nellore races. The Guzera females showed better adaptation to the restricted diet, with increased rumination, which resulted in increased digestibility.