体外产气法评价青海高原燕麦青干草与天然牧草组合效应

本研究采用体外产气法评价了青海高原反刍家畜补饲用燕麦青干草分别与藏嵩草、金露梅+珠芽蓼、线叶嵩草3种天然牧草均按0∶100,25∶75,50∶50,75∶25,100∶0的比例两两组合后的发酵产气特性。结果表明,48 h产气量、理论最大产气量与NDS(P＜0.01)呈正相关关系,而与NDF(P＜0.01)、HC(P＜0.01)呈负相关关系;产气速率常数与HC(P＜0.01)呈负相关关系;产气延滞时间与ADF(P＜0.001)、NDF(P＜0.05)呈正相关关系,而与CP(P＜0.01)、NDS(P＜0.05)呈负相关关系。不同牧草组合在发酵12～24 h的正组合效应较高,且随着发酵时间的延长,各组合均呈组合效应量逐渐减弱的变化趋势;且以燕麦青干草作为补饲草进行该地区天然草地反刍家畜的冷季营养补饲时,燕麦青干草分别与藏嵩草、金露梅+珠芽蓼、线叶嵩草草地型牧草均以50∶50比例组合较为合适。因此,做好牧草间的科学搭配组合是提高青海高原天然草地冷季牧草利用率的有效途径之一。

Evaluation of the fermentation characteristics of mixed oat green hay and native pastures in the Qinghai plateau using an in vitro gas production technique

In vitro gas production was used to evaluate for ruminants the fermentation characteristics of mixed oat green hay supplemented with native Kobresia tibetica,Dasiphora fruticosa+Macrophyllous knotweed,and linear leaf Kobresia at ratios of 0∶100,25∶75,50∶50,75∶25 and 100∶0 in the Qinghai plateau.The 48 h gas production and theoretical maximum gas production were positively related to neutral detergent soluble(NDS) content but negatively related to neutral detergent fibre(NDF) and hemicellulose(HC) contents.Gas producing velocity was negatively related to HC content.The lag times were positively related to acid detergent fibre(ADF) and NDF contents,and negatively related to crude protein(CP) and NDS contents.The positive associate effects of different pasture combinations were greater during 12-24 h fermentation,and there was a declining trend of the associate effects as fermentation time increased.When using oat green hay as a nutritional supplement to the ruminants grazing on native grassland,the mixture of oat green hay with the native pastures of K.tibetica,D.fruticosa+M.knotweed,linear leaf Kobresia at a ratio of 50∶50 was appropriate.Therefore,choosing the optimal combination is an effective way to improve the utilization of cold-season pastures of native grasslands in the Qinghai plateau.