Constipated 5 Y. O

Hi mommies my lo ever since ang bowel movements niya is every few days or sometimes once a week tapos lagi pa siya nag ppoop sa undies niya. Feeling ko yung milk is the culprit kasi her milk is NIDO 4+ and NIDO talaga milk niya ever since nag wean kami sa breastmilk.. Ano po maissuggest nio na alternative milk sa NIDO considering her constipation? Thank you