dear friend... you should stop giving powder milk regularly. you can use cow's milk. its better than powder milk. nothing wrong in giving cows milk to the baby. but please check with milk provider. some persons will mix packet milk with cows milk and they circulate it. this kind of milk is not good for children.
now your child is 1 yr old so you can give solid foods like rice, idly, egg etc to them. are you breastfeeding to your kid? if so you can cont it to six more months. it will gives great strength to your son.
you can give him fruits, fruit juices, cooked lentils, sundals, cooked vegetables, egg...
reduce the milk count (cows milk/powdermilk) for the day and practice him with the solid foods, fruits and vegetables.