放牧条件下藏系绵羊妊娠母羊采食量及营养盈缺状况研究

Study on Feed Intake and Nutritional Surplus and Deficiency Status of Tibetan Ewes under Grazing Conditions

为了解西藏当雄天然草地牧草营养成分的季节性变化,掌握西藏放牧妊娠母羊在不同时期牧草采食量及营养动态,从而分析放牧绵羊的营养盈缺状况,确立补饲标准,用饱和炼烷烃法对藏系绵羊不同时期牧草放牧采食量进行测定,并参照NRC推荐的需要量进行分析比较。结果表明:(1)高山草甸和河滩草甸牧草营养成分随季节变化明显,春季返青期和夏季旺盛期牧草的粗蛋白(CP)含量显著高于秋冬枯草期(P<0.05),而中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)的含量显著低于秋冬枯草期(P<0.05);钙、磷含量在不同时期差异不显著(P>0.05)。(2)高山草甸旺盛期和枯草期,放牧妊娠母羊干物质日采食量差异不显著(P>0.05);(3)河滩草甸旺盛期和枯草期,放牧妊娠母羊干物质采食量枯草期干物质采食量显著高于旺盛期(P<0.05)。研究结果显示,西藏当雄高山草甸和河滩草甸牧草营养价值随季节变化明显,春季返青期和夏季旺盛期牧草营养价值显著高于秋冬枯草期;高山草甸和河滩草甸枯草期放牧妊娠母羊干物质采食量均高于旺盛期,但高山草甸冬季枯草期及河滩草甸夏季旺盛期放牧妊娠母羊摄入钙、磷不足。

In order to investigate the seasonal changes of the nutrient composition of the natural grassland in Dangxiong Tibet,and to know the feed intake and nutrient dynamics of Tibetan grazing pregnant ewes during different pasture periods,then analyzing their nutritional surplus and deficiency status and establishing supplementary feeding standard,the experiment determined the feed intake of Tibetan sheep at different pasture periods on different meadows using the saturated alkanes method,and analysed the data in comparison to the NRC sheep nutrient requirements.The results showed that:(1)the nutrient composition of pasture in alpine meadow and river beach meadow changed significantly with season.The CP content in the greening stage and vigorous period was significantly higher than that in dry grass stage(P<0.05),and the ADF and NDF content were significantly lower than that in dry grass stage(P<0.05).There were no significant differences of Ca and P content in different stages(P>0.05).(2)Daily feed intake of dry matter in vigorous and hay period of the alpine meadow were not significantly different(P>0.05).(3)The daily feed intake in dry hay period was significantly higher than that in vigorous period(P<0.05).The study showed the nutrient composition of pasture in alpine meadow and river beach meadow changed significantly with season.The nutritional value of forage in the greening stage and vigorous period was significantly higher than that in dry grass stage.The dry matter intake of pregnant ewes in dry grass stage was higher than that in vigorous period.However,the intake of CP and P could not meet the growth needs of Tibetan pregnant ewes in the dry hay period of alpine meadows and vigorous period of river meadows.