皖草2号、墨西哥玉米营养价值的调控研究

Regulation on Forage Nutritive Value of Wancao 2 and Zea mexicana Forage Crops

对杂交苏丹草———皖草2号、墨西哥玉米进行不同刈割频度和青贮等调控试验,结果表明:不同刈割频度鲜干物质产量差异极显著,皖草2号和墨西哥玉米鲜物质产量分别刈割三次和两次最高;干物质产量随着刈割次数增加而减少,皖草2号显著高于墨西哥玉米。皖草2号刈割三次粗蛋白质(CP)产量和总能量最高,高于墨西哥玉米,CP含量前者低于后者。两作物第一次收获期的干物质(DM)和CP瘤胃降解率最高,而后再生草降解率逐渐降低,粗纤维降解率逐渐增加,皖草2号略高于墨西哥玉米。青贮后皖草2号头茬草酸洗纤维含量、再生草粗灰分含量和干物质、粗蛋白质、粗纤维降解率均高于青贮前。两种饲用作物营养价值差异是由于其生物学特性的差异所致,调控措施对其有显著影响。

Sudan Grass Wancao 2 and Zea mexicana were stuadied, the results indicated that the difference of the fresh matter and dry matter yield were significant under different harvesting frequency. The fresh matter yield of Sudan Grass-Wancao 2 and Zea mexicana were the highest when cut 3 times and 2 times respectively, in the whole growth period. The dry matter decreased when the harvesting times in- creased, the dry matter yield of Wancao 2 was significantly higher than that of Zea mexicana , The crude protein （CP） yield of Wancao 2 was the highest when it was cut 3 times, and higher than that of Zea mexicana, but the former CP content was lower than that of the later. The total energy （GE） of Wancao 2 was the highest when it was cut 3 times. The ruminal degradation rate of dry matter and CP was the highest at the first harvest stage, which decreased significantly in the regrown grass, the digestibility rate of acid detergent fiber （ADF） increased gradually. Wancao 2 was higher than Zea rnexicana. As for Wancao 2, the content of crude ash （CA） and ADF were higher after silaging. The degradation rates of the CP, acid de- tergent fiber and dry matter were also higher after silaging. In conclusion, the difference of the two kind of forage crops was caused by their difference of biological characteristics and the regulated measurements.