The objective of this experiment was to evaluate the effect of corn grain maturity and air exposure time prior to ensiling on the carbohydrate concentration of corn silage from corn crop planted late in the season. A complete randomized design was used with a 2 x 4 factorial arrangement, testing two stages of maturity at harvest (MK - milky kernel and MDK - ½ milky and ½ dough kernel) of maize crops and four air exposure time prior to ensiling: 0, 12, 24 and 36 hours. Harvests occurred in 2004 on April 26th and May 18th. Stage of maturity (M) and periods of air exposure (TE) showed significant effects as well as interactions in most of tested variables. DM content was different according to M and TE. The MK and MDK silages showed different residual sugar and starch concentrations, respectively, 1.51 and 1.31% and 4.23 and 13.21% of DM. Soluble sugars decreased with TE with values of 1.64% (DM basis) with zero h air exposure to 1.05% after 36 hours exposure. The greatest impact of TE was observed on NDFap values (NDF corrected for ash and protein). Even a short 12-hour period of air exposure before ensiling affects negatively the nutritional value of corn silages.
ADF; lignin; NDF; OM; soluble sugars; starch
