不同生长期白羊草的营养成分及绵羊瘤胃降解特性

为研究不同生长期白羊草(Bothriochloa ischaemum Keng)营养成分的变化规律及营养成分的瘤胃降解规律,试验选用15只安装永久性瘤胃瘘管的肉用绵羊,采用半体内法(in situ)对不同生长期白羊草营养成分的降解规律进行测定。结果表明,不同生长期白羊草的各营养成分均差异显著(P<0.05)。随生长期的推进,粗蛋白质(CP)、粗灰分(Ash)、粗脂肪(EE)、钙(Ca)和磷(P)含量不断降低,而有机物(OM)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)和酸性洗涤木质素(ADL)含量不断增加。白羊草干物质(DM)、OM、NDF和ADF的72 h降解率及有效降解率均随生长期的推进不断降低,而CP有效降解率以拔节期最高,其次是抽穗期。综合考虑白羊草各生长期的营养含量及产量,以及营养成分的瘤胃降解特性,建议白羊草的最佳利用时期为抽穗期。

Nutrient Contents and Rumen Degradability Characteristics of Bothriochloa ischaemum at Different Growth Stages

In order to investigate the change rule and the rumen degradation rule of nutritive contents of Bothriochloa ischaemum at different growth stages, Fifteen mutton sheep fitted with permanent rumen fistula were selected to estimate the rumen degradation rule of nutritive contents of B. ischaemum at different growth stages in situ. The results showed that the nutritive contents of B. ischaemum at different growth stages had significant differences (P<0.05). With the progress of maturity, the contents of crude protein (CP),crude ash (Ash), ethanol extract (EE), calcium (Ca) and phosphorus (P) decreased, whereas the contents of organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) increased. The disappearance rate at 72 h and effective degradation rate of dry matter (DM), OM, NDF and ADF of B. ischaemum decreased with the development of growth period. The effective degradation rate of CP in jointing stage was the highest, followed by the heading stage. The comprehensive consideration of nutrient contents, nutrient yields and rumen degradation characteristics suggested that B. ischaemum should be harvested in heading stage.