Nutrient components and rumen degradability dynamics of White clover at different growth stages | 白三叶不同生育期营养成分及其绵羊瘤胃降解动态研究

中国人. 研究不同生育期白三叶的营养成分含量变化及其瘤胃降解动态。采集分枝期、抽茎期、开花期和成熟期白三叶样品,测定其营养成分含量，并选择装有永久性瘤胃瘘管的小尾寒羊与杜泊羊杂交一代羊研究其瘤胃降解动态。白三叶中粗蛋白（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）、钙（Ca）、磷（P）含量在不同生育期差异显著（P＜0.05），CP、Ca、P含量随着生育期的推进呈下降趋势, NDF、ADF含量呈上升趋势,CP含量呈现“高-低-高-低”的变化趋势。随白三叶生育期的推进，其总氨基酸（TAA）含量呈现“高-低-高-低”的变化趋势，TAA/CP和总必需氨基酸/非必需氨基酸（TEAA/NEAA）呈现出“低-高-低”的单峰变化趋势；干物质（DM）、CP、NDF的瘤胃有效降解率呈明显下降趋势（P＜0.01）,CP和DM有效降解率接近，NDF的有效降解率最低。综合考虑白三叶不同生育期的产量、营养成分及其瘤胃降解动态，建议白三叶在开花期刈割利用。

英语. This paper was engaged in the study on nutrient components and rumen degradation characteristics of white clover at different growth stages. Six sheep fitted with permanent ruminal cannulas were used to determine the degradation profiles of nutrient components at different growth periods in the rumen by nylon-bag technique. The results showed that significant differences existed in CP, NDF, ADF, Ca and P content at different growth stages (P＜0.05). As the maturity progressed, CP, Ca and P decreased. CP varied with a regular tall-low-tall-low double apex rhythm, NDF and ADF content increased. TAA varied with a regular tall-low-tall-low double apex rhythm, but the TAA/CP and TEAA/ NEAA varied with a regular single low-tall-low apex rhythm. DM, CP and NDF showed a trend of decrease for rumen degradation (P＜0.01), but CP and DM showed closer degradation rate, NDF was the lowest. Based on nutrient components, rumen degradation characteristics and its output, it’s advisable that white clover is utilized at abloom stages.