Abstract: This research is aimed to explore the grazing productivity of alfalfa mixtures grassland and integrate the total grass-fed mode of lamb fattening by rotational grazing. In 2017-2018,the lamb grazing experiment was carried out in the international agricultural high-tech industry park of Chinese Academy of Agricultural Sciences in Langfang,Hebei province. The data of aboveground biomass of grassland,weight gain of lamb and meat quality had been measured. The results showed that the aboveground biomass of alfalfa mixtures was over 11.2 t DM·hm^-2,and the crude protein was 20.92% in May. The biomass,metabolic energy and crude protein in each hectare of alfalfa mixtures can meet the requirements of 51 fast-growing lambs 150 days,and each lamb gained 30 kg body weight. Meanwhile,the content of Omega-3 polyunsaturated fatty acid (PUFA) in outer ridge was significantly increased,and the n-6/n-3 ratio was 2.72,which significantly improved the quality of lamb meat. The total grass-fed mode of lamb fattening by rotational grazing on alfalfa mixtures grassland has a broad application prospect and is of great significance to the development of alfalfa industry and grassland animal husbandry in China.

Key words: Alfalfa mixtures, Total Grass-fed mode, Lamb grazing, Metabolic energy, Polyunsaturated fatty acid

摘要： 本研究旨在探讨紫花苜蓿（Medicago sativa L.）混播草地放牧利用的生产潜力和集成全草型集约化肉羊放牧育肥技术模式。2017-2018年，在位于河北省廊坊市的中国农业科学院国际农业高新技术产业园内开展了2年羔羊育肥的划区轮牧试验，研究了紫花苜蓿混播草地的地上生物量、育肥羊增重以及羊肉品质的变化规律。结果表明：混播草地地上生物量超过11.2 tDM·hm^-2，5月份紫花苜蓿混播草地的粗蛋白为20.92%，每公顷紫花苜蓿混播草地可满足51只育肥羊、放牧育肥150天，每只增重30 kg所需的干物质、代谢能和粗蛋白三个方面的全部需求。与此同时，紫花苜蓿混播草地还可以显著增加羊肉中欧米伽3型多不饱和脂肪酸的含量，n-6/n-3比例为2.72，羊肉健康品质显著提高。以紫花苜蓿混播草地为基础的全草型肉羊放牧育肥技术具有广阔的应用前景，对我国苜蓿产业以及草地畜牧业发展具有重要意义。

关键词: 紫花苜蓿混播草地, 全草型模式, 肉羊放牧, 代谢能, 多不饱和脂肪酸