In Vivo and In Vitro Evaluation of Alkaline, Acid, and Physical Treatments of Whole Plant Sorghum Grain Silage for Cattle1

Whole plant sorghum grain silage (WPS) was harvested at 40% dry matter and stored in plastic bag silos to investigate the influence of chemical and physical processing upon nutrient utilization. An IVDMD study compared four different chemicals applied as a percent of WPS dry matter (AH = 1% ammonium hydroxide, SH = 1.5% sodium hydroxide, SA = 1.5% sulfuric acid, and C = control) and three physical processes (rolled WPS, selective rolling of grain in WPS, and nonrolled control WPS) in a factorial arrangement. An interaction (P < .01) between chemical treatment and physical WPS processing was observed when grain and stover were subjected separately to IVDMD procedures. Rolling of WPS, grain, or chemical treatments resulted in similar grain IVDMD after 48 h. Physical processing of stover and grain was associated with less variable IVDM than chemical treatments. A cattle feeding study was conducted to compare WPS treated (percent of DM) with either 1.8% anhydrous ammonia (AA), 2.0% sodium hydroxide (SH), or 1.8% sulfuric acid (SA), or untreated WPS to serve as control (C). Steers fed AA WPS gained 24% more (P < .05) live weight more (P < .05) efficiently and retained 28% more (P < .05) empty body energy than steers fed C WPS. Similar parameters for steers fed either SH or SA WPS indicated opposite (P < .05) trends when compared to steers fed C WPS. This probably resulted from improper incorporation of these chemicais into WPS with spray nozzles attached to a commercial Silopress at time of filling 100-t plastic silos.