Many brands of baby formula are made from cow's milk. However, it does not mean that your infant is ready to start on milk before the age of 1.
Breast milk and baby formula are made for baby's developing digestive system. They are both easier to digest and have the right balance of protein, vitamins, and minerals. It is all the nutrition your baby needs before starting solid foods. In fact, the protein content in cow's milk can actually do damage to your little one's kidneys at this stage.
Breast milk and baby formula are also high in iron. Your baby won't get enough iron and other nutrients if their main source is replaced with cow's milk.