Study On Herbage Intake And Analysis Of The Nutrient Surplus And Defict Of Grazing Sheep In Seasonal Change

Shaertao Mountains had rich forage resources at Zhao Su County in Xin Jiang. In order to find out nutrients of seasonal change in natural grassland pasture, understand herbage intake and digestibility of grazing sheep in seasons, experiments by the following areas of research and analysis:(1) Take samples of grass in four seasons pasture, analysis of the nutrients content, grasp the nutrition danamic change regulatuion. Using n-alkanes as markers to estimate the herbage intake and digestibility of grazing sheep, grasp the herbage intake of seasonal change.(2) According to grassland yield, with the national standard, calculating reasonable grassland’s carrying capacity. According to herbage intake,calculating actual grassland’s carrying capacity, using overgrazing rate evaluating pasture carrying capacity.(3) According to metabolic energy and crude protein intake in daily of grazing sheep, with nutrition requirements of sheep, analysis nutrient surplus and defict of grazing sheep in four seasons. Results showed that:(1)Herbage nutrient content with seasonal change is obvious in Zhao Su, expressed as CP、DE、ME content are summer>autumn>spring>winter, ADF、NDF content are winter>autumn>spring>summer. Herbage intake of growing ewes in four seasons were 856.92、1063.84、1241.40、661.68 g/d respectively, dry matter intake were 1.60%、3.27%、3.33%、1.67% of weight respectively; Herbage intake of mature ewes in four seasons were 1021.83、1324.43、1585.82、876.97 g/d respectively, dry matter intake were 2.06%、2.61%、3.17%、2.02% of weight respectively. Herbage intake of grazing sheep in summer had higher than that in other seasons(p<0.05), herbage intake of grazing sheep in winter was lowest.Herbage intake of grazing sheep were satisfy in spring, summer and autumn. Herbage intake of grazing sheep was deficient in winter. The dry matter digestibility of growing ewes in four seasons were 45.85%、56.50%、50.44%、39.05% respectively; The dry matter digestibility of mature ewes in four seasons were 50.50%、60.94%、55.52%、45.76%. The dry matter digestibility of grazing sheep in summer had higher than that in other seasons(p<0.05).(2)Pasture carrying capacity in four seasons were summe>autumn>spring and winter, pasture overgrazing rate in four seasons were 76.26%、35.87%、13.48%、105.37% respectively, winter and autumn were serious. Reasonable and actual grassland’s carrying capacity with seasonal change is obvious, suffers form forage yield and forage utilization.(3)Rumen ammonia N concentrations of grazing sheep in summer was highest, rumen ammonia N concentrations of growing ewes and mature ewes were 12.92 mg/100 m L、15.96 mg/100 m L respectively, it were extremly higher than winter and spring(p<0.01),it was higher than autumn(p<0.05). TVFA of growing ewes and mature ewes in summer were 6.23 mmol/100 m L、6.55 mmol/100 m L respectively, it was higher than that other seasons(p<0.05).PUN of growing ewes and mature ewes in summer were 20.29 mg/100 m L、25.73 mg/100 m L, it was higher than that other seasons(p<0.05). Rumen fermentation level of grazing sheep in summer was highest, winter and spring were lowest. ME intake of growing ewes in four seasons were 8.01、10.74、9.58、6.87 MJ/d?head respectively; ME intake of mature ewes in four seasons were 9.20、12.21、11.65、9.05 MJ/d?head respectively. ME intake of sheep in summer had higher than that in winter and spring(p<0.05). ME intake of growing ewes in spring and winter were deficient, ME intake of mature ewes in winter was deficient, it is necessary to supple energy feeds. CP intake of growing ewes in four seasons were 86.65 、155.66、115.48、55.60 g/day?head respectively;CP intake of mature ewes in four seasons were 109.63、180.61、143.87、89.20 g/day?head respectively, CP intake of grazing sheep in summer had higher than that other seasons(p<0.05), CP intake of growing ewes and mature ewes in winter were deficient.Ca intake of growing ewes in four seasons were 8.82、10.72、15.65、6.62 g/d?head respectively; Ca intake of mature ewes in four seasons were 10.53、13.34、19.98、8.77 g/d?head respectively,P intake of growing ewes in four seasons were 2.74、3.43、3.84、1.98 g/d?head respectively; P intake of mature ewes in four seasons were 3.23、4.10、4.91、2.63 g/day?head respectively.Ca and P intake of sheep were satisfy with requirements of the sheep.