My lo is on formula and he's 4 months and 11 days old, can I start cow's milk in less quantity??

Cow's milk can only be given after your baby attains one year. Before that, it can be harsh on her delicate stomach. You can even feed her goat milk, which is supposed to be gentle and nutritious for babies, but only after one year. Till then, either formula or beastfeeding should suffice, apart from solid food.