西藏高寒草原5种牧草养分含量及体外消化率季节变化

为掌握西藏自治区岗巴县高寒草原天然牧草养分含量及消化率季节变化规律,选取垫型蒿、高原鸢尾、藏羊茅、藏西嵩草和线叶嵩草5种牧草,分别分析8月、10月和12月各种牧草的粗蛋白质、脂肪、灰分、钙、磷和中、酸性洗涤纤维含量及干物质和纤维组分体外消化率.结果 表明:5种牧草中垫型蒿的粗蛋白质含量最高(17.28％)、线叶嵩草次之...

Seasonal Changes of Nutrient Content and in vitro Digestibility of Five Grass Species in Tibetan Alpine Grassland

This study was aimed to understand the seasonal changes in nutrient content and digestibility of natural grasses on the alpine grassland in Kamba county,Tibet.Five grass species,Artemisia minor,Iris collettii,Festuca wallichanica,Kobresia deasyi and Kobresia capillifolia,were separately collected in August,October,and December from local pasture to determine the contents of crude protein(CP),ether extract(EE),ash,calcium(Ca),phosphorus(P),neutral detergent fibre(NDF)and acid detergent fibre(ADF),was well as in vitro digestibility of dry matter(DM),NDF and ADF.The results showed that among the five grass species,Artemisia minor had the highest CP content of 17.28%,followed by Kobresia capillifolia(15.73%),and Festuca wallichanica had the lowest CP content(3.15%).The ranges of EE and ash contents of the five grass species were 1.31%~1.84%and 2.57%~9.90%,respectively.The Ca content of the five grass species ranged from 0.27%to 4.94%,but their P content was relatively stable in a narrow range from 0.09%to 0.23%.For NDF and ADF contents,Iris collettii had the highest values(84.42%and 54.44%,respectively),while Kobresia deasyi and Kobresia capillifolia had lower values.With seasonal changes,CP content gradually decreased and fiber fractions of grasses,except Kobresia deasyi,gradually increased(P<0.05).No significant change was found in EE among seasons,but ash firstly increased and then decreased with season change.Ca content of the five grass species had a huge variation between species and seasons,while P content decreased with seasonal changes,except for Iris collettii.Kobresia deasyi and Kobresia capillifolia had the highest in vitro digestibility of DM(71.55%and 68.42%),NDF(53.36%and 54.45%)and ADF(42.10%and 45.02%),followed by Artemisia minor and Festuca wallichanica,and the lowest values were found in Iris collettii(except August).Except for Kobresia deasyi,the rank of in vitro digestibility of DM,NDF and ADF of other four grass species were shown as follows:August>October>September.In conclusion,in ultra-high altitude alpine grassland of Kamba county,nutritive value of Kobresia deasyi and Kobresia capillifolia is superior to Festuca wallichanica and Artemisia minor,and Iris collettii has a lowest nutritive value.