Alfalfa is primarily stored as silage or hay in livestock production. Previous research has shown that the storage method of grass significantly influences milk composition. This study aimed to investigate milk production performance and lipid composition in dairy cows fed diets consisting of alfalfa hay or alfalfa silage as roughage. Forty-two mid-lactation Holstein dairy cows were selected and randomly divided into three groups, each receiving a total mixed ration consisting of alfalfa hay (AH), 50% alfalfa silage + 50% alfalfa hay (AHAS), or alfalfa silage (AS). The results showed that milk fat content (P = 0.049) and milk fat yield (P < 0.001) were significantly higher in the AH and AHAS groups compared to the AH group. With increased supplementation of alfalfa silage in the diet, ω-3 polyunsaturated fatty acid content increased significantly (P < 0.001), while ω-6 polyunsaturated fatty acid content (P = 0.007) and the ratio of ω-6 to ω-3 polyunsaturated fatty acids decreased (P < 0.001). The contents of sphingomyelins, phosphatidylserines, phosphatidylethanolamines, and phosphatidylglycerols in the AHAS and AS samples were higher than in the AH samples, although the differences were not statistically significant. Additionally, the content of phosphatidylcholines was significantly higher in the AS group compared to the AH group (P = 0.032). In conclusion, feeding dairy cows a diet consisting of alfalfa silage can increase the major phospholipid content and polyunsaturated fatty acid composition in raw milk, which is more conducive to human health. These findings provide valuable insights into the benefits of alfalfa silage for dairy cows.

中文翻译：

---

饲喂含有苜蓿干草的日粮与苜蓿青贮饲料的泌乳奶牛的乳脂组学谱的变化


紫花苜蓿主要作为青贮饲料或干草储存在畜牧生产中。先前的研究表明，草的储存方法对牛奶成分有显着影响。本研究旨在研究饲喂以苜蓿干草或苜蓿青贮饲料作为粗饲料的日粮的奶牛的产奶性能和脂质组成。选择 42 头泌乳中期荷斯坦奶牛并随机分为三组，每组接受由苜蓿干草 （AH）、50% 苜蓿青贮饲料 + 50% 苜蓿干草 （AHAS） 或苜蓿青贮饲料 （AS） 组成的总混合日粮。结果显示，AH 和 AHAS 组的乳脂含量 （P = 0.049） 和乳脂率 （P < 0.001） 显著高于 AH 组。随着日粮中紫花苜蓿青贮饲料添加量的增加，ω-3 多不饱和脂肪酸含量显著增加 （P < 0.001），而 ω-6 多不饱和脂肪酸含量 （P = 0.007） 和 ω-6 与 ω-3 多不饱和脂肪酸的比值降低 （P < 0.001）。AHAS 和 AS 样品中鞘磷脂、磷脂酰丝氨酸、磷脂酰乙醇胺和磷脂酰甘油的含量高于 AH 样品，但差异无统计学意义。此外，与 AH 组相比，AS 组磷脂酰胆碱的含量显著升高 （P = 0.032）。综上所述，给奶牛喂食以苜蓿青贮饲料为主的日粮，可以提高生牛乳中主要的磷脂含量和多不饱和脂肪酸组成，更有利于人体健康。这些发现为紫花苜蓿青贮饲料对奶牛的好处提供了宝贵的见解。