D.W.
You aren't giving him cow's milk at 8 months are you!? If so, stop immediately! His system isn't ready to handle cow's milk. It has way too much protein, not enough essential fats that he needs, too much sodium, etc.
Same with juice! He doesn't need juice at all.
Breastmilk or formula is primary nutrition for the entire first year. The entire first year! Solids are for practice and a minor supplement. My second wouldn't touch solids until she was 9 months old. No big deal! She nursed well, gained weight perfectly on track.