本试验旨在借助开路式呼吸测热系统研究饲粮非纤维性碳水化合物(NFC)/中性洗涤纤维(NDF)对生长期杜寒杂交母羊生长性能、营养物质表观消化率及甲烷产量的影响.采用单因素试验设计,选取体况良好、体重为(27.8±0.5)kg的母羊30只,根据体重一致原则,分配到3组,各组饲粮NFC/NDF分别为0.78(精粗比为35:65)、1.03(精粗比为50:50)、2.17(精粗比为65:35),每组10只羊.试验期为25 d,包括3 d调整期、7 d预试期和15 d正试期.结果表明:在NFC/NDF=0.78组自由采食和其他组限饲条件下,3组试验羊的初始体重和结束体重以及平均日增重无显著性差异(P>0.05).当饲粮NFC/NDF由0.78增加至2.17时,干物质采食量显著降低(P<0.05),干物质、有机物和粗蛋白质表观消化率显著增加(P<0.05),NDF和酸性洗涤纤维(ADF)表观消化率无显著性差异(P>0.05).当饲粮NFC/NDF由0.78增加至2.17时,甲烷能、单位干物质采食量的甲烷产量、单位总能摄入量的甲烷能产量显著降低(P<0.05).结果提示,在平均日增重一致的前提下,高NFC/NDF饲粮料重比较低,且甲烷转化效率较低;对生长期杜寒杂交母羊来说,限饲条件下饲喂NFC/NDF为2.17的饲粮在提高生产效益的同时又兼顾甲烷减排,效果相对最佳.%The objective of the present study was to investigate the effects of dietary non?fiber carbohydrate (NFC)/neutral detergent fiber(NDF)on growth performance, nutrient apparent digestibility and methane e?missions of Dorper and thin?tailed Han crossbred ewes using open?respiration system. Thirty healthy ewes weighted(27.8±0.5)kg were allocated to three groups, with a single factor experiment design, according to their body weight. Dietary NFC/NDF was 0.78,1.03 and 2.17, respectively, and concentrate to forage ratio was 35:65, 50:50 and 65:35, respectively. Each group had 10 ewes. The whole experiment lasted for 25 d with 3 d of adjustment,7 d of pre?test and 15 d of test. The results showed as follows: under the condition of ad libitum in NFC/NDF=0.78 group and dietary restriction in other groups, there were no significant differ?ences in initial body weight, final body weight and average daily gain(ADG)among groups(P>0.05). As dietary NFC/NDF increased from 0.78 to 2.17, dry matter intake(DMI)was significantly decreased(P<0.05), whereas dry matter, organic matter and crude protein apparent digestibility were significantly increased (P<0.05), but no significant differences were observed in NDF and acid detergent fiber(ADF)apparent di?gestibility among groups(P>0.05). As dietary NFC/NDF increased from 0.78 to 2.17, methane energy, methane emission per unit of DMI, methane energy emission per unit of gross energy intake were significantly decreased(P<0.05). In conclusion, under the similar ADG, lower feed to gain ratio and methane emission are observed in high NFC/NDF diet; it is appropriate to offer growing ewes diet with NFC/NDF of 2.17, which can increase production efficiency and control methane emission.
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