Chemical Composition and Fermentation Characteristics of Silages of Potato, Sweet Potato and Turnip with Rice Straw and Studies the Effect of Rations Containing Its Silages on Performance and Economical Efficiency of Growing Lambs

The objectives of this study were evaluation the silages containing non-commercial potato tubers, sweet potato roots, and turnip roots mixing with rice straw and its effect on lambs' performance. Silages were making automatically in bags. Chemical composition and fermentation characteristics were measured for these silages. Twenty-four lambs averaged weight 19.4 kg were divided into four groups to evaluate 4 rations (6 in each): Ration A was 100% of CP requirements according to NRCfrom CFM + Rice straw ad lib. Rations B, C and D were 60% of CP requirements according to NRC from CFM + silages ad lib. of potato, sweet potato and turnip, respectively for 28 weeks. The lambs were weighed biweekly. Digestibility trials and animal performance were conducted to evaluate rations A, B, C and D. Results showed that DM of potato silage, sweet potato silage and turnip silage was 38.15, 38.34 and 32.25%, respectively. OM was 85.46, 83.97 and 88.47%, respectively. CP was 12.06, 13.56 and 11.16%, respectively. Fermentation characteristics of silages of potato, sweet potato and turnip explained that pH was 4.09, 3.80 and 4.07, respectively. Ammonia-N was 0.28, 0.29 and 0.26 g/100g DM, respectively. Ammonia-N% of total N was 14.68, 13.46 and 14.59, respectively. Acetic acid was 2.77, 2.66 and 3.20g/100g DM, respectively. Butyric acid was 0.44, 0.73 and 0.83g/100g DM, respectively. Lactic acid was 7.01, 7.43 and 8.64g/100g DM, respectively. Digestion coefficients of rations A, B, C and D was DM digestibility was 68.03, 54.60, 63.28 and 57.75%, respectively, OM digestibility was 70.39, 59.09, 64.58 and 61.1%, respectively, CP digestibility was 70.41, 64.20, 71.69 and 65.50%, respectively, CF digestibility was 55.64, 53.07, 52.65 and 49.11, respectively, EE digestibility was 90.74, 86.11, 88.61 and 89.02%, respectively and NFE digestibility was 73.30, 58.56, 65.56 and 62.12%, respectively. TDN was 67.96, 55.52, 60.34 and 59.5%, respectively and DCP was 10.46, 9.52, 11.08 and 9.62%, respectively. Ruminal pH after feeding was significantly decreased than before feeding and the differences among all rations were not significant at 4h post feeding. Ruminal pH values in all rations ranged from 5.58 to 6.91. Ruminal NH₃-N and total VFA were significantly increased after feeding than before feeding. NH₃-N in the rumen of ration C was significantly lower than other rations while the differences among other rations were not significant. The differences of ruminal VFA's among all rations were not significant except rations A was significantly lower than other rations. Microbial protein of rations A, B, C and D was 0.26, 0.39, 0.37 and 0.39 gm/100 ml rumen liquor, respectively. The average DM intake of rations A, B, C and D was 1.285, 0.942, 0.955 and 0.901 kg/lamb/d, respectively, daily body gain was 107.99, 109.69, 112.24 and 120.75 g/lamb/d, respectively and feed conversion was 11.90, 8.56, 8.53 and 7.45 Kg DM/Kg gain, respectively. The feed cost of rations A, B, C and D was 5.806, 4.402, 4.892 and 4.283 LE/lamb/d, respectively and economical efficiency was 1.12, 1.49, 1.38 and 1.69, respectively.