The Study Of Optimization About Yak-sheep Production System In Alpine Meadow In Eastern Qilian Mountain

Tibetan Plateau is vital ecological area and important animal husbandry region in China. However, the degraded grassland and low livestock production limited the sustainable development in term of society, economy and environment. Finding a solution is the challenge for government, scientists and pastoralists at present.This study was conducted in the Qilian Mountains alpine meadow area from 2012 to 2014. The purpose was to optimize the whole grass-livestock production system, which were improvement of sown pasture with planting high quality forage and drying forage, rangeland management with deferred grazing and feterliaztion as well as livestock production with crossbrdding,fatterning and supplementary feeding in winter. The indexes in term of forage grass(yield,ADF,NDF,EE,CP,CA), vegetation community(coverage,height,density,frequency,biomass,the number of the flowering and fruiting), soil enzyme activity(catalase, urease, invertase, phosphatase), livestock growth(body size, weight) and slaughter index of livestock(slaughter rate, cooked rate, tenderness) were measured. The results showed as follows:1. Under the seeding rate of 450 kg/hm2,nitrogen quantity of 75 kg/hm2, phosphorus quantity of 150kg/hm2, oat production and quality to achieve the optimal. The total plants, height, production reached 626.00 ten thousand plants/hm2, 121.02 cm, 44004.00kg/hm2 respectively, the content of CP, NDF,ADF was 9.57%、35.2%、48.5% respectively.2. The order of drying rate of six drying methods for oats at three growth stages was KH2PO4 spray with shade drying> sun drying with fracturing>NaHCO3 spray with shade drying>CaCO3 spray with sun drying> sun drying> shade drying on a hayrack.; Under the same hay drying method, the drying time of oats cut at either anthesis or postulation stage was longer than when oats were cut at the heading stage. There were significant influences and an interaction between drying methods and growth stage on ADF(except in postulation period), NDF, crude protein, coarse ash, crude fat(except in postulation period). Based on the comprehensive evaluation of oats drying methods and growth stage using the grey correlation analysis and entropy method, the better drying methods were CaCO3 and KH2PO4 spray with sun drying when oats were cut at the heading stage, These two methods can produce the high quality oats hay and are easily applied in field.3. The plant community under deferred grazing were the plant height, coverage, biomass of each paddock increased with the grazing time was deferred, Although, the number of plant flowering in the longest deferred grazing paddock were significantly lower than that in other three paddocks(P<0.05), the total number of seeding were significantly higher than that in others(P<0.05). The results reveled that the deferred grazing in spring on the winter-spring pasture is good management for control rangeland degradation in alpine meadow.4. Rangeland fertilaztion can increased soil urease activity, catalase activity, alkaline phosphatase activity. But the influences of four kinds of fertilizer on soil invertase activities is not significant(P>0.05) to controls under different fertilizer rate. Fertilization can promote the importance value of gramineae and reduce he importance value of forbs, fertilization can increase the biomass also. Compound fertilizers are best.5. The economic benefit of adult cattle of the supplements with 2 kg/d/head was the best and reached 99.6RMB Yuan/head. the plant community on the grassland with combination of feeding and grazing were better than the grassland with only grazing, the flowering and seeding rate of forage on the grassland with combination of feeding and grazing were significant higher than that on the grassland with only grazing(P<0.05), feeding and grazing were united in wedlock could improve the situation in alpine meadow; the yak calves did not recommend to feed the oats in winter.6. Sheep crossbreeding: the birth weight of Ola(♂)×Tibetan sheep(♀)was 4.63 kg, which is significant higher than other crossbreed lambs(P<0.05); the body weight of Bond(♂)×Tibetan sheep(♀)from 1 to 5 months were higher than others, and the daily body weight gain(0.19kg/d) was significant higher than others(P<0.05). The dressing percentage of Ola(♂)×local alpine merino(♀)was 46.29%, the highest one in all crossbreeds. The viscera weight of crossbreed Tibetan sheep was higher than Gansu alpine merino. The ratio of holding water, cooked meat percentage, tenderness of Ola(♂)×local Tibetan sheep(♀)were 38.70%, 64.40%, 71.18 N,respectively, which were higher than others. The pH of the purebred local Tibetan lamb was 7.1, which was the highest value in crossbreed lambs. The assessment of meat color, marbled meats, mutton odor was same among different hybridized lambs. Considering production in practice, the Ola(♂)×Tibetan sheep(♀)is the best hybrid combination.7. The daily bodyweight gain of Tibet lamb and fine wool lamb were higher than the control groups. The daily bodyweight gain of fine wool lamb were significant higher than Tibet lamb(P<0.05). The effect of body weight gain and economical benefit of Tibet lamb were 0.25 kg/day and 38.7 RMB Yuan/lamb, which were the best one in three treatments of Tibet lamb. The effect of body weight gain and economical benefit of fin wool lamb were 0.3 kg/day and 180.6 RMB Yuan/lamb, which were the best one in three treatments of fine wool lamb. We concluded that the fine wool lamb is the optimal livestock breed for stall feeding in the region.