It is strange that you have tried so many antibiotics for loose motions.
In lose motions there are specific indications for antibiotics which will be decided by the pediatrician
In recurrent loose stools one has to exclude both lactose intolerance
and milk protein allergy
.In milkprotein allergy both buffalo milk and formula will produce diarrhea-one has to try soya milk based formula in this case of intolerance.if your child has been growing well inspite of this it may a just temporary lactose intoerance.get a second opinion
from the pediatrician if you are confused do not change milk by yourself!!!