Composição bromatológica de silagens de milho comerciais produzidas no Brasil

The objective was to perform the exploratory analysis of the chemical composition results and the use of models to estimate the total digestible nutrients of the corn silage samples generated from 12 years of commercial analyzes of the Animal Nutrition Laboratory of the Instituto de Zootecnia (IZ), in Nova Odessa, SP, Brazil. As a criterion, samples of corn silage had no additives, 220 samples in the periods from 2004 to 2015 were grouped in four triennia. These were characterized by their chemical composition through descriptive statistical analysis, Pearson correlations and the use of TDN estimation models, using four models of equations: one from Clemson University, one according Harlan and two according Kearl (1 and 2). The nutritional value of corn silage samples was of medium quality, with NDF values (49.2 to 57.2% of MS) above the ideal. All the equations could be used to estimate the NDT (variation of 54.3 to 67.0% in the triennia), Kearl 1 and Clemson showed the highest and the lowest variation between the triennia, respectively. The increase in nutrient value and TDN in triennial 3 and 4 indicates improvement in silage quality.