The Effects of Adding Urea or Urea Plus Molasses in Some Sorghum Varieties Harvested at Dough Stage on Silage Quality and Digestible Dry Matter Yield

Abstract

The aim of this study was to evaluate the effects of the addition of 0.5% urea or 0.5% urea plus 4% molasses into some sorghum varieties (Gozde, P-988, Grazer and Grass-II) harvested at the dough stage on silage quality, in vitro dry matter (DM) digestibility and digestible DM yields. Triplicate silage samples from each variety and treatment group, a total of 36 silage samples, were prepared in 1 l mino-silos and incubated for 90 days. Silage DM and crude protein (CP) levels ranged from 29.56 to 33.46%, and from 7.16 to 12.63%, respectively. Addition of urea or urea + molasses increased CP. and urea + molasses increased DM but decreased the NDF content of all silages (P < 0,05). Silage pHs were between 4.08 and 4.71, and the addition of urea and urea + molasses increased silage pH (P < 0,05). Lactic, acetic and butyric acid concentrations of silages, on DM bases, ranged from 3.50 to 8.01%; from 0.58 to 1.44% and from 0.01 to 0.14%, respectively. The addition of urea and urea + molasses increased the lactic acid and decreased the propionic acid concentration of silages (P < 0,05), although butyric acid concentrations were not affected. Urea supplementation did not affect acetic acid concentrations, and urea + molasses increased the acetic acid concentration of silages. In vitro DM digestibilities of Gozde, P-988, Grazer and Grass-II varieties were 52.85, 54.20, 54.96 and 54.39%, respectively. The addition of urea + molasses to Gozde increased in vitro DM digestibilities, but urea and urea + molasses addition decreased in vitro DM digestibilities in other varieties (P < 0,05). The P-988 variety had the highest digestible DM yield (804.38 kg/decare)(P < 0.05). In conclusion, the P-988 sorghum variety seemed to be the best suited Van ecological conditions based on silage fermentation quality and digestible DM yield.