Effects of sodium diacetate and molasses on the fermentation quality and aerobic stability of total mixed ration silages containing straw

This study explored the effects of sodium diacetate and molasses on the fermentation quality and aerobic stability of silage with rice straw, corn stalk, whole bead, and fine material. The experiment was divided into four groups: control group (C, no additive), sodium diacetate group (S, 0.5% FW), molasses group (M, 3% FW), sodium diacetate and molasses group (SM, 0.5% + 3% FW). After 35 days of fermentation, all total mixed rations (TMRs) were exposed to air and samples were analyzed on the 0th, 3rd, 6th, 9th, 12th, and 15th days for analysis of their aerobic stability. All silages were of good quality having low pH value, low ammonia/total nitrogen, very low propionic acid (1.06～1.54 g·kg^–1 DM) and butyric acid (1.66～4.64 g·kg^–1 DM) content. For aerobic stability, S group was the greatest stability (> 312 h), and higher than (P < 0.05) C (> 216 h) and M (> 288 h) groups. Furthermore, in the whole aerobic exposure stage with S group, aerobic microorganisms and yeasts were at a lower number, the pH value remained at about 4.50 after 12 days of aerobic exposure, the acetic acid content was at a higher level (2.12 g·kg^–1 DM), prolonging aerobic stability. Therefore, it was suggested that 0.5% sodium diacetate could be used to produce TMR silages.