Nutritive values of soybean silages ensiled with maize at different rates

Abstract

One of the major uses of soybean crops (Glycine max (L.) Merril) is as silage. However, due to its unpleasant odour and relatively high butyric acid content, soybean silage is not readily preferred by animals. Because it does not have a regular fermentation, easily fermented forage resources are needed to obtain quality silage. To improve the quality of the silage, soybeans can be mixed with an appropriate amount of maize (Zea mays L.). In this study, we examined the quality and properties of maize (M) and soybean (S) silages of different mixtures (100 % M, 100 % S, 10 % S + 90 % M, 20 % S + 80 % M, 30 % S + 70 % M, 40 % S + 60 % M, 50 % S + 50 % M, 60 % S + 40 % M, 70 % S + 30 % M, 80 % S + 20 % M and 90 % S + 10 % M). For this purpose, each plant species was grown separately, and the maize was harvested when the plants reached the doughy stage. The harvest was performed using a single row maize harvester that chops the plants into 1.5-2 cm pieces. The fresh plant material from each species was then mixed in different proportions and squeezed before being transferred to 1.5 L anaerobic jars (Le Parfait, France). The jars were opened after a 60-day ensiling period. Then, the dry matter rate, pH, silage loss, fleig point, crude protein content, ADF content and NDF content of the silages were determined. The results showed that an increase in soybean rate in the mixture decreased the dry matter rate. Conversely, the silage pH, crude protein content and ADF content increased. Our results suggested that producing quality silage required the soybean material to be mixed with a minimum of 50 % maize.