Losses, chemical composition and aerobic stability of rye silage cv. Temprano subjected to different pre-flowering cuttings with or without fungicide

The present study evaluated the fermentation, chemical characteristics and ruminal disappearance of dry matter of silages of rye cv. Temprano harvested at the stage of floury grain, managed with or without cutting at the vegetative stage and with or without application of Fluxapyroxad + Pyraclostrobin-based fungicide at the pre-flowering phenological stage. This was a 2x2 factorial randomized block experimental design, with 2 cutting regimes (0 and 1 cut) and 2 application management (with and without fungicide), with six replications, where each repetition is represented by a plot of 9.45m², with the treatments SC-SF: without cut at the vegetative stage and without fungicide application; SC-CF: without cut at the vegetative stage with fungicide application; UC-SF: a cut at the vegetative stage with pre-flowering fungicide application; UC-CF: a cut at the vegetative stage and without fungicide application. UC-CF silages were better in the general context, due to the better fiber composition with an average 6.75% reduction in neutral detergent fiber and acid detergent fiber and a 17.10% reduction in lignin content, but, due to its higher DM content, it presented a less efficient fermentation process in terms of organic acid concentration and aerobic stability. However, it did not change the DM losses or ruminal degradability, and there is also the use of DM harvested at the vegetative stage that certainly has a superior quality. The use of fungicide provided only better dry matter index and better fiber composition and improved the fermentation process resulting in lower DM losses without altering the aerobic stability of silages.