Cow milk is very different from human milk because

Cow milk is very different from human milk because it has less carotene.
Breast milk is a complete source of nutrients as well as antibodies, growth factors, and bioactive components such as carotenoids in good amounts. It is established that β-carotene is present in cow milk but absent in buffalo, goat and ewe milk.
Beta-carotene, a major milk carotenoid, is a vitamin A precursor. The high concentration of β-carotene enhances milk's natural properties and provides a valuable source of vitamin A to the consumer.