Cow milk is easier to digest than buffalo milk

Buffalo milk is heavy, difficult to digest.

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there is a general notion that not to feed children with buffalo milk & feed only cow’s milk in some regions, and vice versa, not to feed cow’s milk but feed only buffalo milk in some other regions in India. 

Simple logic is to stick to the regional practice.
Cow milk is easier to digest than buffalo milk

http://easyayurveda.com/2011/04/20/buffalo-meat-buffalo-milk-and-buffalo-products-benefits-and-ayurvedic-explanation/