The Effects of Adding Urea or Urea + 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 (Gözde, 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 Gözde, P-988, Grazer and Grass-II varieties were 52.85, 54.20, 54.96 and 54.39%, respectively. The addition of urea + molasses to Gözde 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.

Keywords: Sorghum silage, urea and molasses supplementation, in vitro digestibility, digestible dry matter yield

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