Agroscope, 1725 Posieux, Switzerland

Influence of storage period on the quality of a maize silage

On farms, sometimes maize is ensiled after harvest and the removal (feed-out) and feeding of the maize silage begun immediately. An experiment was conducted to investigate the effect of this approach on fermentation quality, microbiological quality and aerobic stability. For this, six 700-litre containers were filled with maize having an average dry-matter content of 37 %. With three of the containers, the feed-out period started the day after ensiling; three other containers were sealed, and the feed-out phase started only after a two-month storage period. The following three treatments were applied both to the silage removed immediately and to the silage fed out after the two-month storage period: (1) 5 cm layer fed out daily; (2) 10 cm layer fed out daily; (3) 5 cm layer fed out daily, with the maize having been treated with a silage additive at the time of ensiling. In the silages whose feed-out period started the day after ensiling, fermentation and lowering of the pH were slow to occur, and the silages were characterised by a high charge of yeasts, moulds and bacteria. Even in their containers, the silages were already warm and aerobically instable. This was also the case where the silage had been treated with the additive. According to these results, the removal and feeding of the maize silage immediately after ensiling cannot be recommended. After the two-month storage period, the lactic fermentation process in the silages was completed, the charge of the various microorganisms was in most cases in the normal range, and the silages had a better aerobic stability. Both the removal of a larger layer and treatment with a silage additive improved the aerobic stability of the silage yet further.

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