The aim of this study was to determine the methane (CH₄) mitigation potential of 3-nitrooxypropanol and the persistency of its effect when fed to dairy cows in early lactation. Sixteen Holstein-Friesian cows (all multiparous; 11 cows in their second parity and 5 cows in their third parity) were blocked in pairs, based on actual calving date, parity, and previous lactation milk yield, and randomly allocated to 1 of 2 dietary treatments: a diet including 51 mg of 3-nitrooxypropanol/kg of dry matter (3-NOP) and a diet including a placebo at the same concentration (CON). Cows were fed a 35% grass silage, 25% corn silage, and 40% concentrate (on dry matter basis) diet from 3 d after calving up to 115 d in milk (DIM). Every 4 weeks, the cows were housed in climate respiration chambers for 5 d to measure lactation performance, feed and nutrient intake, apparent total-tract digestibility of nutrients, energy and N metabolism, and gaseous exchange (4 chamber visits per cow in total, representing 27, 55, 83, and 111 DIM). Feeding 3-NOP did not affect dry matter intake (DMI), milk yield, milk component yield, or feed efficiency. These variables were affected by stage of lactation, following the expected pattern of advanced lactation. Feeding 3-NOP did not affect CH₄ production (g/d) at 27 and 83 DIM, but decreased CH₄ production at 55 and 111 DIM by an average of 18.5%. This response in CH₄ production is most likely due to the differences observed in feed intake across the different stages of lactation because CH₄ yield (g/kg of DMI) was lower (on average 16%) at each stage of lactation upon feeding 3-NOP. On average, feeding 3-NOP increased H₂ production and intensity 12-fold; with the control diet, H₂ yield did not differ between the different stages of lactation, whereas with the 3-NOP treatment H₂ yield decreased from 0.429 g/kg of DMI at 27 DIM to 0.387 g/kg of DMI at 111 DIM. The apparent total-tract digestibility of dry matter, organic matter, neutral detergent fiber, and gross energy was greater for the 3-NOP treatment. In comparison to the control treatment, 3-NOP did not affect energy and N balance, except for a greater metabolizable energy intake to gross energy intake ratio (65.4 and 63.7%, respectively) and a greater body weight gain (average 0.90 and 0.01% body weight change, respectively). In conclusion, feeding 3-NOP is an effective strategy to decrease CH₄ emissions (while increasing H₂ emission) in early lactation Holstein-Friesian cows with positive effects on apparent total-tract digestibility of nutrients.

这项研究的目的是确定甲烷（CH ₄）早期泌乳时饲喂奶牛时，3-硝基氧基丙醇的缓解潜力及其作用的持久性。根据实际的产犊日期，胎次和以前的泌乳量，将成对的16头荷斯坦-弗里斯兰奶牛（全部为多胎；第二胎为11头母牛，第三胎为5头母牛）配对，并随机分配给2种日粮中的1种治疗：饮食包括51毫克3-硝基氧丙醇/千克干物质（3-NOP）和饮食，包括相同浓度的安慰剂（CON）。母牛在产犊至牛奶（DIM）至115 d后的3 d饲喂35％的草料青贮饲料，25％的玉米青贮饲料和40％的浓缩饲料（以干物质为基础）。每隔4周，将母牛在气候呼吸室饲养5天，以测量泌乳性能，饲料和养分摄入量，表观养分的总消化率，能量和氮素代谢以及气体交换（每头母牛总共4次造访，分别代表27、55、83和111 DIM）。饲喂3-NOP不会影响干物质摄入量（DMI），牛奶产量，牛奶成分产量或饲料效率。这些变量受哺乳阶段的影响，遵循预期的晚期哺乳模式。饲喂3-NOP不会影响CH在27和83 DIM时_4的产量（g / d），但在55和111 DIM时CH _4的产量平均减少了18.5％。CH ₄产生的这种响应很可能是由于在哺乳的不同阶段采食量的差异所致，因为在饲喂3的每个哺乳阶段，CH _4的产量（g / kg DMI）较低（平均16％）。 -NOP。平均而言，饲喂3-NOP可使H _2的产生和强度增加12倍；对照饮食中，泌乳不同阶段的H ₂产量没有差异，而3-NOP处理的H ₂产量从27 DIM时的0.429 g / kg DMI降至111 DIM时的0.387 g / kg DMI。对于3-NOP处理，干物质，有机物质，中性洗涤剂纤维和总能量的表观总消化率更高。与对照治疗相比，3-NOP不会影响能量和氮平衡，只是更高的可代谢能量摄入/总能量摄入比（分别为65.4和63.7％）和更大的体重增加（平均0.90和0.01％）体重变化）。总之，饲喂3-NOP是减少荷斯坦-弗里斯兰奶牛早期CH ₄排放量（同时增加H ₂排放量）的有效策略，对养分的表观总消化率具有积极影响。