Natural Resources Institute Finland (Luke), Production Systems, 31600, Jokioinen, Finland.
Department of Biology, University of Turku, 20014, Turku, Finland.
Sci Rep. 2024 Jan 5;14(1):613. doi: 10.1038/s41598-024-51300-7.
For sustainable food production selection and breeding of feed efficient animals is crucial. The objective of this study was to evaluate whether multiparous dairy cows, ranked during their first lactation based on residual energy intake (REI) as efficient (low; L-REI) or inefficient (high; H-REI), differ in terms of nutrient use efficiency, methane emissions, rumen fermentation, and gut microbiota composition. Six L-REI and 6 H-REI cows were offered two diets with either a low or high proportion of concentrates (30 vs. 50% of DM) on two consecutive periods of 21 d. Gas exchanges, milk yield, feces and urine excretions were measured in open-circuit respiratory chambers. The results indicated that L-REI cows had higher methane yields (22.6 vs. 20.4 g/kg DM intake) and derived more energy (energy balance - 36.6 vs. - 16.9 MJ/d) and protein (N balance - 6.6 vs. 18.8 g/d) from the tissues to support similar milk yields compared to H-REI cows. Nutrient intake and digestibility were not affected by REI, and there were no interactions between REI and diet. Milk yield, milk production efficiency, and milk composition were not affected by REI except for milk urea concentration that was higher for L-REI cows (14.1 vs. 10.8 mg/100 ml). The rumen and fecal microbiota community structure and function were associated with both the diet and REI, but the diet effect was more pronounced. The current study identified several physiological mechanisms underlying the differences between high and low REI cows, but further studies are needed to distinguish the quantitative role of each mechanism.
为了实现可持续的粮食生产，选择和培育饲料效率高的动物至关重要。本研究旨在评估在其第一个泌乳期内根据剩余能量摄入（REI）排名的多胎奶牛（低效率；L-REI 和高效率；H-REI）在营养物质利用效率、甲烷排放、瘤胃发酵和肠道微生物群落组成方面是否存在差异。在两个连续的 21 天期间，给 6 头 L-REI 和 6 头 H-REI 奶牛提供两种饲料，一种饲料中粗饲料的比例低（30% DM），另一种饲料中粗饲料的比例高（50% DM）。在开放回路呼吸室中测量气体交换、产奶量、粪便和尿液排泄。结果表明，L-REI 奶牛的甲烷产量（22.6 比 20.4 g/kg DM 摄入）更高，从组织中获得更多的能量（能量平衡-36.6 比-16.9 MJ/d）和蛋白质（N 平衡-6.6 比 18.8 g/d），以支持与 H-REI 奶牛相似的产奶量。REI 对营养物质摄入和消化率没有影响，REI 和日粮之间也没有相互作用。除了乳尿素浓度（14.1 比 10.8 mg/100 ml）更高外，REI 对产奶量、产奶效率和牛奶成分没有影响。瘤胃和粪便微生物群落结构和功能与日粮和 REI 都有关，但日粮的影响更为明显。本研究确定了高和低 REI 奶牛之间差异的几个生理机制，但需要进一步研究来区分每个机制的定量作用。
