Fant P, Mantovani G, Vadroňová M, Sabetti M C, Krizsan S J, Ramin M
Department of Applied Animal Science and Welfare, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden.
Department of Veterinary Science, University of Parma, 431 26 Parma, Italy.
J Dairy Sci. 2025 Sep 25. doi: 10.3168/jds.2025-27007.
The objective of this study was to evaluate the effects of high-oil oats and cold-pressed rapeseed cake (RSC) as dietary ingredients, along with supplementation of 3-nitrooxypropanol (3-NOP), on apparent total-tract digestibility, milk production, and enteric CH emissions in dairy cows fed a grass silage-based diet. Twenty-four lactating Nordic Red cows were grouped into 3 blocks. The experiment was conducted as a cyclic change-over where each treatment had 3 observations per period. The experiment consisted of 4 periods of 28 d each, including 18 d of diet adaptation and 10 d of data and sample collection. The 2 × 2 × 2 factorial design included 2 energy sources (barley or high-oil oats), 2 protein supplements (rapeseed meal [RSM] or RSC), and 3-NOP supplementation at 2 levels (0 or 68 mg/kg of DM), resulting in 8 dietary treatments. The basal diet consisted of 60% grass silage (on a DM basis). Inclusion rates of the experimental concentrates were 27% to 29% and 29% to 31% for barley and high-oil oats, respectively, and 8% to 10% and 10% to 12% for RSM and RSC, respectively. Diets were offered ad libitum as a TMR. Daily DMI, milk yield, BW, and gas emissions were recorded throughout the experiment. Gas emissions were measured using the GreenFeed system. Ether extract (EE) content across experimental diets ranged from 2.9% to 6.1% of DM. Total DMI tended to increase with high-oil oats compared with barley, but decreased with RSC compared with RSM. Digestibility of DM, OM, NDF, and EE decreased with high-oil oats versus barley, and EE digestibility increased with RSC versus RSM. Despite lower nutrient digestibility, milk and ECM yield increased by 2.4 kg/d with high-oil oats compared with barley. Milk yield decreased by 1.1 kg/d and ECM yield tended to decrease by 1.0 kg/d with 3-NOP supplementation. Milk protein concentration decreased with high-oil oats versus barley and with RSC versus RSM. Feed efficiency increased with high-oil oats compared with barley. Daily CH emissions (g/d), CH yield (g/kg of DMI), and CH intensity (g/kg of ECM) decreased by 11.2%, 14.2%, and 15.3%, respectively, when barley was replaced with high-oil oats in combination with RSM but were not affected in combination with RSC. Daily CH emissions, CH yield, and CH intensity decreased by 12.5%, 10.6%, and 12.7%, respectively, when RSM was replaced with RSC in combination with barley but not in combination with high-oil oats. Daily CH emissions, CH yield, and CH intensity decreased by 33.5%, 30.9%, and 31.2%, respectively, with 3-NOP supplementation, with slightly greater efficacy on CH intensity when barley was used as the energy source. Urinary urea concentration was greater with high-oil oats than with barley, and lower with RSC than with RSM, but only in combination with high-oil oats. In conclusion, both high-oil oats and RSC are practical dietary ingredients for reducing enteric CH emissions and CH intensity. High-oil oats may additionally improve feed efficiency and production performance in dairy cows. Supplementation with 3-NOP reduced enteric CH emissions by more than 30% with additive effects when combined with RSC, but negatively affected production performance.
本研究的目的是评估高油燕麦和冷榨菜籽饼（RSC）作为日粮成分，以及添加3-硝基氧丙醇（3-NOP）对以青贮牧草为基础日粮的奶牛的表观全肠道消化率、产奶量和肠道甲烷排放的影响。将24头泌乳期的北欧红牛分为3个组。试验采用循环转换设计，每个处理在每个时期有3次观测。试验包括4个每期28天的阶段，包括18天的日粮适应期和10天的数据及样本采集期。2×2×2析因设计包括2种能量来源（大麦或高油燕麦）、2种蛋白质补充料（豆粕[RSM]或RSC）和2个水平的3-NOP添加量（0或68毫克/千克干物质），产生8种日粮处理。基础日粮由60%的青贮牧草（以干物质计）组成。大麦和高油燕麦的试验精料添加比例分别为27%至29%和29%至31%，RSM和RSC分别为8%至10%和10%至12%。日粮以全混合日粮（TMR）的形式自由采食。在整个试验过程中记录每日干物质采食量（DMI）、产奶量、体重和气体排放。使用GreenFeed系统测量气体排放。各试验日粮的乙醚提取物（EE）含量占干物质的2.9%至6.1%。与大麦相比，高油燕麦使总DMI有增加趋势，但与RSM相比，RSC使总DMI降低。与大麦相比，高油燕麦使干物质、有机物、中性洗涤纤维和EE的消化率降低，与RSM相比，RSC使EE消化率增加。尽管营养物质消化率较低，但与大麦相比，高油燕麦使牛奶和能量校正乳（ECM）产量每天增加2.4千克。添加3-NOP使牛奶产量每天降低1.1千克，ECM产量有每天降低1.0千克的趋势。与大麦相比，高油燕麦使牛奶蛋白质浓度降低，与RSM相比，RSC也使牛奶蛋白质浓度降低。与大麦相比，高油燕麦使饲料效率提高。当大麦与RSM组合被高油燕麦替代时，每日甲烷排放（克/天）、甲烷产量（克/千克DMI）和甲烷强度（克/千克ECM）分别降低11.2%、14.2%和15.3%，但与RSC组合时不受影响。当RSM与大麦组合被RSC替代时，每日甲烷排放、甲烷产量和甲烷强度分别降低12.5%、10.6%和12.7%，但与高油燕麦组合时不受影响。添加3-NOP使每日甲烷排放、甲烷产量和甲烷强度分别降低33.5%、30.9%和31.2%，以大麦作为能量来源时对甲烷强度的效果略好。高油燕麦组的尿尿素浓度高于大麦组，RSC组低于RSM组，但仅在与高油燕麦组合时出现此情况。总之，高油燕麦和RSC都是降低肠道甲烷排放和甲烷强度的实用日粮成分。高油燕麦还可能提高奶牛的饲料效率和生产性能。添加3-NOP使肠道甲烷排放降低30%以上，与RSC组合时有相加效应，但对生产性能有负面影响。
