Effects of Urea or Urea Plus Molasses Supplementation To Silages With Different Sorghum Varieties Harvested at the Milk Stage on the Quality and in Vitro Dry Matter Digestibility of Silages

Abstract

The objective of this study was to evaluate the effects of 0.5% urea and 0.5% urea plus 4% molasses (on weight basis) addition to sorghum silages ensiled using 4 sorghum varieties (Grass II, Grazer, Gozde, and P-988) harvested at the milk stage. Plant materials were ensiled in 1-kg jars and the chemical composition, pH, organic acids, in vitro digestibility (IVDMD) and digestible dry matter yield (DDMY) of the silages were determined. Addition of urea and urea plus molasses to silages increased the crude protein ratio significantly (P < 0.01). However, the addition of urea plus molasses significantly decreased the neutral detergent fiber and acid detergent fiber contents of the silages. Additives significantly increased the pH values of the silages. The addition of urea and urea plus molasses to silages generally did not affect acetic or propionic acid content; however, the butyric acid content of the urea and urea plus molasses groups was higher than that of the control groups. IVDMD of all sorghum varieties decreased with the addition of urea and urea plus molasses. Additives did not affect DDMY. In conclusion, the addition of 0.5% urea and 0.5% urea plus 4% molasses to sorghum silages, harvested at the milk stage, improved the CP content of the silages, but they had no positive effect on silage quality, IVDMD or DDMY.