Evaluation of Silages of Potato, Sweet Potato and Turnip with Rice Straw or Wheat Straw with or without Urea and Studies the Effect of Rations Containing Its Silages on Digestion Coefficients and Rumen Fermentation in Sheep

The objectives of this study were evaluation the silages containing of non-commercial potato tubers, sweet potato roots, and turnip roots. Silages were making manually in jars in the 1^st experiment with mixing cutting tubers or roots with rice straw or wheat straw with urea additives at levels0, 0.5% and 1% for determining chemical composition and fermentation characteristics of silages. In the 2^nd experiment, silages were making manually in bags with mixing cutting tubers or roots with rice straw + 2% molasses with 0 or 0.5% urea for evaluating seven rations by rams as follows: Ration A 100% of CP requirements according to NRC (1985) from concentrate feed mixture (CFM) + rice straw ad lib.  Rations B, C and D were 60% of CP requirements from CFM + silages of potato, sweet potato and turnip, respectively. Rations E, F and G were 60% of CP requirements from CFM + silages of potato, sweet potato and turnip containing 0.5% urea, respectively. Silages were fed ad lib. Digestion coefficients and rumen fermentation were conducted to evaluate rations A, B, C, D, E, F and G using 21 local rams (3 in each) averaged weight 49 kg. Results explained that DM% of potato tubers, sweet potato and turnip roots were 18.18, 20.08 and 7.50%, respectively and CP% was 13.31, 10.46 and 13.46%, respectively. DM of potato silage ranged from 34.31 to 35.68%, sweet potato silage ranged from 34.39 to 35.73% and turnip silage ranged from 31.57 to 37.71%. CP in silage with urea was higher than silage without urea. Silage fermentation characteristics explained that pHranged from 3.80 to 4.20, Ammonia-N% of total N ranged from 9.61 to 16.22%, Acetic acid ranged from 2.36 to 3.52 g/100g DM, Butyric acid ranged from 0.28 to 1.34 g/100g DM and lactic acid ranged from 6.31 to 9.65 g/100g DM. Ammonia-N as g/100g DM was increased with increasing urea levels. The differences of DM intake as % of LBW among all rations containing silages were not significant. Digestion coefficients of DM, OM of ration A was significantly (P<0.05) higher than all rations and the differences among other rations containing silages were not significant. Digestion coefficients of DM of rations containing silages ranged from 52.88 to 56.94%, OM ranged from 54.69 to 59.03% and CP ranged from 58.61 to 64.8%. TDN of control was 60.49 and other rations containing silages ranged from 51.61 to 55.83%. DCP of control was 8.08 and other rations ranged from 7.79 to 9.58%. Digestion coefficients and nutritive values were not affected with urea additives. Ruminal parameters indicated that the differences of ruminal pH among all rations were not significant at 4h post feeding. The differences of NH₃-N and Total VFA's among rations B, C and D were not significant and the differences among rations E, F and G were not significant at 2 and 4h post feeding. The NH₃-N and VFA's of rations containing silages with urea was significantly (P<0.05) higher than control and rations containing silages without urea. The differences of Microbial protein among all rations were not significant except ration B was lower than other rations.