Hello i have gone through your complaints. Actually cows milk has more solute load which falls on your baby kidney
which is partially immature to handle the load. Even though it is earlier to start of the cows milk it is not absolutely contraindicated. You can try for lactose free milk diet for your twin A for few days which will decrease the bloating
and it will be more safer if you start the cows milk at least after completing 4 months .
Thank you. Good day