The present study examined the effect of replacing cereal grain with a fibrous by-product concentrate on nutrient intake, milk production traits and fatty acid composition, diet digestibility, feed conversion efficiency (FCE), CH₄ and CO₂ emissions, and plasma blood parameters of dairy cows in early lactation. Twenty-two Nordic Red cows were randomly assigned to one of two dietary treatments immediately after calving until 18 weeks in lactation. The cereal grain treatment contained 593 g/kg of grass silage, 317 g/kg of cereal grain mixture (barley, oat, and wheat), 79 g/kg of heat-treated rapeseed meal, and 11 g/kg of a mineral mix on a DM basis. A mixture of unmolassed beet pulp, wheat middlings, barley fibre, and wheat bran replaced cereal grains in the by-product treatment. The diets were isocaloric and isonitrogenous and were fed ad libitum as total mixed rations. The by-product diet had a higher fibre content, while starch content was reduced compared with the cereal grain diet. Despite the 12 %-unit difference in dietary starch content, no differences in DMI were observed. Similarly, no differences in body weight and body condition score (BCS) were observed between treatments. Cows fed the fibrous by-product diet had lower apparent total-tract digestibility of DM (683 g/kg), organic matter (700 g/kg), and crude protein (665 g/kg) compared to those fed cereal grain diet (735, 749, and 699 g/kg, respectively), but milk yield and composition, as well as FCE were not affected by treatment. The edible feed conversion ratio in the by-product group was on average 3.7- folds higher than the cereal grain group. Total CH₄ emission (g/d) and CH₄ yield (g/kg DMI) reduced by 10.3% on average when by-product replaced cereal grains, but CH₄ intensity (g CH₄/kg ECM) was not significantly influenced by diet. Although the feeding of by-product had no effect on milk fat content, it changed its fatty acid profile by increasing the proportion of some unsaturated fatty acids (ƩC18:1 trans, C18:3 cis-9 cis-12 cis-15, omega-3) in milk fat. Replacing cereal grain with fibrous by-product in the diets of early lactation dairy cows had no effect on their risk of developing metabolic disorders. These findings suggest that cows fed grass silage-based diets can be supplemented with fibrous by-product concentrates without affecting feed efficiency or energy balance status, thereby supporting sustainable food production. However, future works should evaluate the economic aspects of feeding by-product concentrates to determine their practical application for feed manufacturers and farmers.

本研究研究了用纤维状副产物浓缩物替代谷物对营养摄入，牛奶生产性状和脂肪酸组成，饮食消化率，饲料转化效率（FCE），CH ₄和CO _{2的影响。}泌乳早期奶牛的尾气排放和血浆血液参数。产犊直至哺乳18周后，立即将22头北欧红牛随机分配为两种饮食疗法之一。谷物谷物处理包含593 g / kg的草料青贮饲料，317 g / kg的谷物谷物混合物（大麦，燕麦和小麦），79 g / kg的热处理菜籽粕和11 g / kg的矿物质混合物在DM基础上。在副产品处理中，将未捣碎的甜菜浆，小麦中段，大麦纤维和麦麸的混合物代替了谷物。日粮是等热量和等氮的，随意进食，以总混合日粮的形式进食。与谷物日粮相比，副产品日粮的纤维含量较高，而淀粉含量降低。尽管膳食淀粉含量差异为12％，但未观察到DMI差异。类似地，在治疗之间没有观察到体重和身体状况评分（BCS）的差异。与饲喂谷类谷物的母牛相比，饲喂纤维状副产品的母牛的表观总消化率低（683 g / kg），有机物（700 g / kg）和粗蛋白（665 g / kg）。分别为735、749和699 g / kg），但牛奶产量和组成以及FCE不受处理的影响。副产品组的可食用饲料转化率平均比谷物谷物组高3.7倍。总CH 和分别为699 g / kg），但牛奶产量和组成以及FCE不受处理的影响。副产品组的可食用饲料转化率平均比谷物谷物组高3.7倍。总CH 和分别为699 g / kg），但牛奶产量和组成以及FCE不受处理的影响。副产品组的可食用饲料转化率平均比谷物谷物组高3.7倍。总CH当副产品替代谷物时，平均₄排放量（g / d）和CH ₄产量（g / kg DMI）平均降低了10.3％，但日粮对CH ₄强度（g CH ₄ / kg ECM）的影响不明显。尽管副产物的添加对牛奶中的脂肪含量没有影响，但它通过增加一些不饱和脂肪酸（18C18：1反式，C18：3顺式-9顺式-12顺式）的比例来改变其脂肪酸谱-15，omega-3）中的牛奶脂肪。在早期泌乳奶牛的日粮中用纤维状副产物代替谷物，对它们发生代谢紊乱的风险没有影响。这些发现表明，饲喂草类青贮饲料的母牛可以补充纤维状副产品浓缩物，而不会影响饲料效率或能量平衡状态，从而支持可持续的粮食生产。但是，未来的工作应评估饲料副产品浓缩物的经济方面，以确定其在饲料生产商和养殖者中的实际应用。