青海省海晏县牧场牧草营养品质全年动态

Annual analysis of nutritional quality of pasture in Haiyan County,Qinghai Province

为弥补众多青藏高原定点监测全年牧草营养价值变化对生产支撑不足的问题,探明青藏高原放牧牦牛全年轮牧条件下牧草的全年动态营养价值,本研究选取青藏高原典型牧户的放牧草地,于2015年9月到2016年8月全年跟踪放牧牦牛、模拟采集可食性牧草,并分析牧草常规营养成分及总能,采用体外两阶段法测定牧草体外干物质消化率。结果表明,1)牧草中粗蛋白(CP)、粗脂肪(EE)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、粗灰分(Ash)、钙(Ca)和磷(P)含量分别为3.68%~19.21%、0.86%~2.74%、9.65%~43.83%、44.70%~76.23%、5.40%~9.62%、2.13%~5.12%和0.027%~0.190%,5月份CP、Ash含量极显著高于其他月份(P<0.01);2)体外两阶段法评定牧草体外干物质消化率得出,消化率为42.72%~72.47%,5月份极显著高于其他月份(P<0.01);3)牧草总能(GE)、消化能(DE)和代谢能(ME)分别为17.76~19.67、7.81~13.26和6.40~10.87 MJ·kg^(-1),全年不同月份牧草GE差异不显著(P>0.05),以6月份最高,11月份次之,牧草DE及ME为5月份显著高于其他月份(P<0.05),4月份和6月份次之,12月份最低。青海省海晏县牧场5月和6月天然牧草品质优良,10月至翌年3月牧草营养价值较低。因此,建议牧民和养殖户在10月到翌年3月采用天然草地配合补饲饲料养殖;鉴于全年轮牧季节性草地类型不同,今后应采取跟踪式牧草营养监测方法,较好地实现放牧牦牛精准补饲。

In order to compensate for the problem of insufficient support for monitoring of the nutrient value of pasture in the Qinghai Tibet Plateau, we examined the dynamic nutritional value of grassland pasture under grazing conditions in the Qinghai Tibet Plateau. During the period September 2015 to August 2016, we selected typical Tibetan herdsmen and grazing pastures to track yak grazing, and simulated the collection of edible forage for sampling. The nutrient composition and total energy of the pasture were analyzed, and the dry matter digestibility of pasture was determined using a two step in vitro method. The following results were obtained. 1） The contents of crude protein, ether extract, acid detergent fiber, ash, calcium, and phosphorus were 3.68%~19.21%, 0.86%~2.74%, 9.65%~43.83%, 44.70%~76.23%, 5.40%~9.62%, 2.13%~5.12%, and 0.027%~0.190%, respectively, and the contents of CP and ash in May were significantly higher than those in other months （P〈0.01）. 2） The digestibility of pasture was 42.72%~72.47%, which was significantly higher than that of other months （P〈0.01）. 3） Total energy （GE）, digestive energy （DE）, and metabolic energy （ME） were 17.76~19.67, 7.81~13.26, and 6.40~10.87 MJ·kg-1, respectively. There was no significant difference in the GE of forage in different months （P〉0.05）, although it was the highest in June, followed by November. DE and ME were significantly higher in May than in other months （P〈0.05）, and the lowest in December, followed by April and June. In conclusion, the natural forage of Haiyan County, Qinghai Province in May and June is of good quality, whereas in October to March, the nutritional value of forage is low. Therefore, in view of the different types of seasonal grassland grazing throughout the year, it is recommended that pastoralists and farmers use natural grassland to supplement feed for breeding yaks in October to March. In the future, we will conduct follow up monitoring of forage grass, and determine the fine feeding of grazing yak.