if child is not gaining proper weight you need to consult your doctor to rule out the cause and most of the time it could be because of nutritional deficiencies like nutritional anemia and some  other factors like malabsorption any chronic disease like congenital heart disease or  some chronic infection specially urine infection or worm infestation  should be checked if required .

There could be other reasons of inadequate weight gain. You should get your bbay checked with a Paediatrician once. Try to improve your nutrition and take plenty of water. Dont give any animal milk to the baby till one year of age. You can start semi-solid food after 6 months of age along with breast feeds.

Need to take to improve breastmilk

Avoid buffalo milk or cow milk till 1 year Mother milk is sufficient What is weight of baby