Características de fermentação da silagem de seis variedades de milho indicadas para a região semiárida brasileira

The fermentation characteristics and silage quality of six maize varieties of early and super early cycles were evaluated. They are recommended for the Brazilian semi-arid region (BRS Caatingueiro, BRS Assum Preto, BR 5033 - Asa Branca, BR 5028 - São Francisco, Gurutuba and BRS 4103). Experimental silos were used, in a completely randomized design, with six treatments (varieties) and four replicaties. The evaluated parameters were: dry matter (DM), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), total carbohydrates (CHO), non-fibrous carbohydrates (NFC), pH, ammoniacal nitrogen as part of the total nitrogen (N-NH₃/TN), organic acids, and in vitro dry matter digestibility (IVDMD) of the silages. The mean values found for silage were: DM= 29.6%; OM= 94.9%; CP= 8.2%; NDF= 49.9%; ADF= 27.5%; EE= 3.8%; CHO= 82.7%; NFC= 32.8%; pH= 3.8; N-NH₃/TN= 2.9%/TN; lactic acid = 7.6%; acetic acid = 0.6%; butyric acid = 0.3%; and IVDMD = 57.9%. Varieties BR 5028 - São Francisco and Gurutuba stood out (P<0.05) from others in relation to dry matter. The BRS Caatingueiro showed higher (P<0.05) level of non-fiber carbohydrates in relation to the others. The silages from all the varieties were considered of excellent quality, with potential to be conserved as silage in the Brazilian semi-arid.