| Summary: | 碩士 === 國立宜蘭大學 === 動物科技學系碩士班 === 100 === Abstract
Rice crop is the major organic crop in Taiwan. When the organic rice grain is harvested so is organic rice straw, which could be used for organic feeding. However, rice crop production is seasonal. Organic rice straw would not be available for feed on a daily basis. Proper preservation is deemed necessary for a constant feed supply. Comparing hay production, making silage is less proned to weather changes and may improve forage quality. Inoculating lactic acid bacteria at ensiling has been used to ensure fermentation quality. However, heat produced during the intial days may inhibit lactic acid bacteria. Streptococcus thermophilus (ST) can survive at high temperature and may be a better silage lactic acid bacteria.
Experiment 1 evaluated effect of inoculating conventional and organic rice straw with ST at ensiling on chemical composition and fermentation quality. In comparison to conventional rice straw, organic rice straw had higher crude protein (CP) and acid detergent fiber concentration before ensiling and lower pH, neutral detergent fiber and ammonia concentration. Inoculating ST did not affect lactic acid and volatile fatty acid (VFA) concentration, but decreased pH faster during early days after ensiling.
Experiment 2 compared chemical composition and fermentation quality of organic rice straw silage made from the same rice paddy over 4 years. Rice straw pH and dry matter were 5.9-6.5 and 34-38% before ensiling. These data changed by year. After ensiling, all silage pH fell below 4.8. Treatment with ST decreased initial silage pH. Silage chemical composition was affected by year, but not ST. Lactic acid and VFA concentration were not affected by treatment.
Experiment 3 investigated effect of feeding organic rice straw silage to wether dairy goats with low (200 g/d) or high (300 g/d) concentrate supply on feed intake, growth, and plasma characteristics. Goats in both concentrate treatments had weight gain. Forage intake of low concentrate treatment (64.3%) reached the organic farming standard (60%), but not high concentrate (55.9%). Organic feed intake of both treatments were below 85%.
Experiment 4 evaluated effect of partial replacement of concentrate with organic rice bran on nutrient utilization in weather dairy goats fed organic rice straw silage. Quantity of forage and organic feed supply was based on data from experiment 3. The results obtained show that both forage (low rice bran: 77.4%; high rice bran: 79.3%) and organic feed (low rice bran: 87.4%; high rice bran: 91.6%) intake fulfilled constraints for organic feeding. High rice bran inclusion decreased CP intake by goats.
In conclusions, the chemical composition and fermentation quality of organic rice straw silage was better than those of conventional. Inoculating ST could decrease silage pH faster but not for conventional rice straw. Feeding more rice bran could help to reach organic feeding standard but may to not satisfy protein requirement for goats.
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