Cow milk is rich in proteins, fats, carbohydrates, and minerals, and its nutrient content depends on various factors. We tested differences in fatty acid and protein contents of milk from seven breeds and regions, including three dairy breed samples: Holstein milk from Beijing, China (BH); Holstein milk from Hebei province, China; Jersey milk (JS); and four dairy/meat cow samples: Sanhe milk, Xinjiang brown milk (XH), Simmental milk, and Shu Xuanhua milk. Breed significantly affected total fat, fatty acid, and protein contents. The region significantly affected the contents of different fatty acids, α-lactalbumin, and lactoferrin. JS had the highest total fat, most fatty acids, and casein contents. XH performed well with significantly higher unsaturated fatty acid content than BH, which was not significantly different from JS, and its protein composition of low β-lactoglobulin and high lactoferrin was more similar to breast milk, which may thus be favorable to the growth and development of children. Our results may inform the development of dairy products from different cow breeds and advance the process of accurate breed identification.