Abstract Impact of herbage proportion, breed, average days in lactation (ADiL), and season on bulk milk composition of 12 dairy farms were investigated over a year using a mixed effect model approach. A 10%-points higher proportion of herbage led to higher contents of omega 3 (n-3) fatty acids (FAs), conjugated linoleic acids (CLA), vaccenic acid, and branched chain FAs (+0.08, +0.08, +0.19, +0.05 g 100 g−1 fat, respectively). Breed influenced n-3 FAs and CLA (+0.31, +0.17 g 100 g−1 fat, respectively), κ-casein, lipoprotein lipase, β-lactoglobulin, total whey protein, fatty acid synthase, and glycoprotein-2, resulting in +0.96, −0.019, −0.83, −1.12, +0.009, and +0.01 g 100 g−1 measured proteins, respectively, in Brown Swiss milk. ADiL influenced lactoferrin and crude protein; season affected all FAs and proteins examined. The identification of these quantitative relationships allow predictions that provide new insights for the production, processing and commercialisation of grassland-based dairy products.

中文翻译：

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牧草比例、动物品种、泌乳期和季节对牛奶脂肪酸和蛋白质组成的影响

摘要 使用混合效应模型方法研究了牧草比例、品种、泌乳平均天数 (ADiL) 和季节对 12 个奶牛场散装牛奶成分的影响一年多。高 10% 的草本比例导致 omega 3 (n-3) 脂肪酸 (FAs)、共轭亚油酸 (CLA)、异油酸和支链 FAs（+0.08、+0.08、+0.19 , +0.05 g 100 g−1 脂肪，分别）。品种影响 n-3 FAs 和 CLA（分别为 +0.31、+0.17 g 100 g−1 脂肪）、κ-酪蛋白、脂蛋白脂肪酶、β-乳球蛋白、总乳清蛋白、脂肪酸合酶和糖蛋白-2，导致+0.96、-0.019、-0.83、-1.12、+0.009 和 +0.01 g 100 g-1 测量的蛋白质，分别在 Brown Swiss 牛奶中。ADiL 影响乳铁蛋白和粗蛋白；季节影响了所有检查的 FA 和蛋白质。