State Key Laboratory of Grassland Agro-Ecosystems, Key Laboratory of Grassland Livestock Industry Innovation, Ministry of Agriculture and Rural Affairs, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou, China.
Agri-Food and Biosciences Institute, Hillsborough, UK.
J Anim Physiol Anim Nutr (Berl). 2020 Jan;104(1):22-31. doi: 10.1111/jpn.13223. Epub 2019 Oct 9.
Twelve Hu sheep × thin-tail Han crossbred dry ewes with an average body weight of 32.6 ± 0.68 kg and an age of 3 years were arranged in a 3 × 3 Latin square design, with each experimental period of 24 d to evaluate the effect of substituting alfalfa hay in a portion of concentrate on nutrient intake, digestibility, N utilisation efficiency and methane emissions. The ratios of corn straw to alfalfa to concentrate for 3 diet treatments were 60:0:40, 60:15:25 and 60:30:10, respectively. Intake and digestibility were measured for each of the ewes, which were housed in individual metabolism crates for 6 d after an adaptation period of 14 d, and the feed was offered at 1.2 ME to ensure approximately 10% orts. Methane emissions were determined in a respiration chamber for 2 consecutive d. An increase in the levels of alfalfa as a substitute for concentrate significantly increased the roughage, NSC and ADF intake and faecal N output as a proportion of N intake and manure N output. Furthermore, this increase in alfalfa input levels decreased DE, ME and N intake; nutrient digestibility; DE/GE, ME/GE and CH emissions per day; CH output expressed as a portion of the DM, OM and GE intake; and urinary N and ammonia N output, especially between extreme treatments. Alfalfa input levels had no effect on the BW, DM and GE intake; the EB or EB/GE intake; and the retained N. This study indicated that increasing alfalfa input as a substitute for concentrate could significantly decrease the digestibility, CH emissions and urinary N and NH -N outputs; and shift the N excretion from urine to faeces; and could sustain a similar DM intake.
选用平均体重为 32.6±0.68kg、3 岁的 12 只湖羊×小尾寒羊杂交母干羊，采用 3×3 拉丁方设计，每个试验期 24d，研究用部分苜蓿干草替代精料对绵羊养分采食量、消化率、氮利用效率和甲烷排放的影响。3 种饲粮处理的玉米秸秆、苜蓿干草和精料的比例分别为 60∶0∶40、60∶15∶25 和 60∶30∶10。适应期 14d 后，将母羊单笼饲养 6d，测定其采食量和消化率，精料提供的能值为 1.2 代谢能，以确保约 10%的剩料。采用呼吸室法连续 2d 测定甲烷排放量。随着苜蓿替代精料水平的增加，粗饲料、非结构性碳水化合物和酸性洗涤纤维采食量以及粪氮排泄量占氮采食量和粪氮排泄量的比例显著增加。此外，苜蓿替代精料水平的增加降低了消化能、代谢能和氮采食量；养分消化率；每天的消化能/总能、代谢能/总能和甲烷排放量；以干物质、有机物和总能采食量的比例表示的甲烷排放量；以及尿氮和氨氮排泄量，尤其是在极端处理之间。苜蓿替代精料水平对体重、干物质和总能采食量；维持需要的能量或维持需要的能量/总能摄入；以及保留氮无影响。本研究表明，增加苜蓿替代精料可显著降低消化率、甲烷排放量以及尿氮和氨氮排泄量，使氮排泄由尿转向粪，并保持相似的干物质采食量。
