Effects of stage of maturity at harvest, wilting and LAB inoculant on aerobic stability of wheat silages

The objective was to study effects of cultivar, stage of maturity at harvest, wilting, and addition of lactic acid bacterial (LAB) inoculant at ensiling, and their interactions, on the aerobic stability of wheat silages. Wheat of two cultivars, harvested at the flowering or the milk stage of maturity were ensiled in mini-silos, either directly after cutting (DC) or after wilting (W). After 2–7 months of storage, silages were subjected to a 7-day aerobic stability test during which changes in chemical composition, dry matter (DM) and neutral detergent fiber (aNDF) digestibility, and temperature, as well as DM losses and CO2 production, were measured. Silages from wheat cultivar BH were relatively dry (DM between 287 and 430 g/kg) and were mostly stable upon aerobic exposure. The flowering wheat of cultivar Galil was moister (DM of 199 g/kg), and the DC silages were stable upon aerobic exposure. Silages of the wilted flowering wheat (DM of 370 g/kg) spoiled and after 4 and 7 days, produced 15 and 76 g/kg DM CO2, respectively. Silages from the milk stage of this cultivar, both DC and W were unstable, and a homofermentative LAB enhanced aerobic spoilage. Factorial analysis of variance was applied to the results with cultivar, stage of maturity, wilting and inoculant as main effects, as well as their interactions. Cultivar and LAB inoculant had effects on silage composition and aerobic stability, with stage of maturity having an effect on aerobic losses, whereas wilting did not have effects on aerobic spoilage indicators. The inoculant enhanced CO2 production in the silages prepared from the DC wheat of the flowering and milk stages, as compared with the respective non-inoculated control silages which contained high concentrations of VFA. However, in the wilted silages which contained less VFA, both control and inoculated silages deteriorated similarly with time of exposure to air.