Why are infants advised to stop drinking formula at 12 months? What can happen of my baby starts drinking cow milk at 11 months?

Misunderstanding. Cow's milk is allowed at 12 months but this doesn't mean formula has to be stopped at 12 months. A protein in the cow's milk called "heat labile protein" causes occult bleeding from infants' intestine and results in anemia. The intestinal mucosa become more resistant to the protein by 12 moths of age.
1.Cost 2.not much. Infants who have broadened their diet to include a variety of baby/table foods at a year have less need for the balance if nutrients in formula by a year.Parents can choose to continue or drop the expense of formula at that point kids with a diverse diet that start cow milk at 11m are usually fine.Cow milk is designed for calf's & can irritate the human gut.It should be limited to 16-24oz/d.