本试验旨在研究内蒙古呼和浩特地区不同生育期柠条锦鸡儿营养成分的动态变化及其在绵羊瘤胃内的降解特性。分别于孕蕾期、开花期和结实期采集当年生柠条锦鸡儿嫩枝条,测定初水分后在65℃烘箱中烘干,测定常规营养物质含量;选用安装有永久性瘤胃瘘管的内蒙古小尾寒羊3只,采用瘤胃尼龙袋法评定不同生育期柠条锦鸡儿营养成分的瘤胃降解特性。试验结果表明:1)开花期和结实期柠条锦鸡儿的干物质(DM)和粗蛋白质(CP)含量显著高于孕蕾期(P＜0.05);不同生育期柠条锦鸡儿有机物(OM)、粗脂肪和无氮浸出物含量无显著差异(P＞0.05);结实期粗灰分含量显著高于孕蕾期和开花期(P＜0.05);孕蕾期和开花期柠条锦鸡儿中性洗涤纤维(NDF)含量显著高于结实期(P＜0.05),而酸性洗涤纤维(ADF)含量显著低于结实期(P＜0.05);随着生育期的延续,柠条锦鸡儿木质素含量逐渐升高,开花和结实期显著高于孕蕾期(P＜0.05);随着生育期的延续,柠条锦鸡儿钙含量显著提高(P＜0.05),磷含量显著降低(P＜0.05)。2)随着生育期的延续,柠条锦鸡儿DM的72h消失率和有效降解率逐渐降低,开花期和结实期DM的有效降解率无显著差异(P＞0.05);不同生育期柠条锦鸡儿CP的72 h消失率无显著差异(P＞0.05),但有效降解率孕蕾期显著高于开花期和结实期(P＜0.05);随着生育期的延续,柠条锦鸡儿OM和NDF的72h消失率和有效降解率均显著降低(P＜0.05);开花期和结实期柠条锦鸡儿ADF的72h消失率和有效降解率无显著差异(P＞0.05),但显著低于孕蕾期(P＜0.05)。试验结果提示,结合不同生育期柠条锦鸡儿营养物质含量、 饲草DM产量以及营养物质的瘤胃降解特性,开花期柠条锦鸡儿营养物质的利用效率最高,为最佳刈割时期。

This experiment was conducted to investigate the dynamic change and rumen degradation characteristics of Caragana korshinskii nutrients in different growth periods in Hohhot, Inner Mongolia. Twigs of Caragana korshinskii were mowed in budding, flowering and fructicative periods, respectively, and the nutrients were analyzed after determination of initial moisture and then drying in the oven at 65 ℃. Three sheep fixed with permanent rumen fistulas were selected and the rumen nylon bag technique was used to study the rumen degradation characteristics of Caragana korshinskii nutrients in different growth periods. The results showed as followed:1) the contents of dry matter (DM) and crude protein (CP) of Caragana korshinskii in flowering and fructicative periods were significantly higher than those in budding period (P＜0.05); there were no significant differences in the contents of ether extract, nitrogen free extract and organic matter (OM) among budding, flowering and fructicative periods (P＞0.05); the crude ash content in fructicative period was significantly higher than that in budding and flowering periods (P＜0.05); the neutral detergent fiber (NDF) content in budding and flowering periods was significantly increased compared with that in fructicative period, however, the acid detergent fiber (ADF) content was significantly decreased (P＜0.05); the lignin content was increased with the extend of growth period, and the lignin content in the flowering and fructicative periods was significantly increased compared with that in budding period (P＜0.05); the Ca content was significantly increased (P<0.05) but the P content was significantly decreased (P<0.05) with the extend of growth period. 2) Rumen DM disappearance rate at 72 h and effective degradation rate were decreased gradually with the extend of growth period, and effective degradation rate in budding period was significantly higher than that in flowering and fructicative periods (P＜0.05); there were no significant effects for growth period on rumen CP disappearance rate at 72 h (P＞0.05), however, effective degradation rate in budding period was significantly higher than that in flowering and fructicative periods (P＜0.05); with the extend of growth period, rumen disappearance rate at 72 h and effective degradation rate of OM and NDF were decreased significantly (P＜0.05); there were no significant differences in rumen disappearance rate at 72 h and effective degradation rate of ADF between flowering and fructicative periods (P＞0.05), but they were all significantly lower than those in budding period (P＜0.05). It is concluded that Caragana korshinskii has a higher utilization rate in flowering period and it is appropriate for mowing in this period considering nutritive components, grass DM production and rumen degradation characteristics of Caragana korshinskii in different growth periods.