GSD health

Question
dear sir

i got and Belgian Sheared and GSD mix male of 6 month but he seems very small to his age and very slim body previous owner was an illegal breeder so he gave him meat instead of dog food. but now i am trying to feed him on milk and dog food he is not accepting dog food after trying every thing i am also feeding him on boiled beef
sir plz tell me any good idea so he become strong and healthy all other things is good he is active and going with me daily for 2 km walk

Answer
Cows' milk is hard for dogs to digest.  You might try goats' if available.  Better yet would be unsalted chicken broth.  Put a little on his dry dog food and see if he eats it.  You may even have to let him go a few days without eating.  I have done that and it is very hard to do.  Dog food is the only practical way to give a dog the complete and balanced diet it needs.