PSIX-10 - The Effect of NDF from Forage Levels on Metabolize Energy Intake and Fecal Starch in Nelore Cattle

Abstract: The effect of forage in finishing cattle has an important role. Although, it is not common to conduct research this subject with Nelore cattle. The goal of this study was to evaluate the effect of NDF from forage on ME and FS in Nelore cattle. All experiment had been approved by ESALQ animal care council . The diets were composed of corn silage, soybean meal, citrus pulp, ground flint corn, urea, chloride potassium and premix. In this experiment data from 20 Nelore Bulls with initial weight 420kg ± 30 kg were used. The animals received 5 finishing diets for 105 days that were switched every 21 days. The diets started from 15% NDF from forage followed by 12%, 9%, 6% and 3%. The ME was calculated by ME=0.82 DE (NRC, 1976; Garret, 1980), during the entire period of time, using the Grow Safe system. Feces were taken from the ground just after the animals defecated. The feces among those treatments were taken in 2 periods of time during each treatments in 20 animals on d 20 of each diet. Thereafter , FS was measured by NIRS equation developed by Caetano et al. (2009). A proc mixed model was used to perform the statistical analyses in SAS.There was a quadratic effect of NDF from forage in ME intake, P< 0,0001. However, regarding FS there was not any effect due to NDF from forage level. Thereby, the ME intake depends directly of forage levels. It might be explained by the hepatic oxidation theory (Oba and Allen, 2000) as well the rumen fill effect (Mertens 1992). Moreover, the outcomes related the FS and NDF from forage levels were different than expected. Those results were different from the results by Caetano et al. (2015) and De Melo et al. (2019), both that used ground flint corn.