1, "cow's milk" and "milk powder" is no difference. The "milk powder" from the narrow sense, is to refer to cow milk powder. But in a broader sense, there are many kinds of milk powder, such as goat milk powder and cow milk powder. Although goat milk and cow milk powder are both milk powder, but the nutrient composition and source of colostrum are completely different.
2, because the infant formula is mostly cow's milk made of cow's milk, so gradually milk powder is customarily synonymous with milk powder. Only special milk powder, such as goat milk powder will be separate to "goat milk powder" label as a difference.