My parents and sister are giving buffalo's milk to 25 days old kittens, even when we have the mother cat to feed them.
It's like just some moments ago the mother cat was with her kittens in her bed, but the kittens were meowing a lot rather than feeding on milk form their mother. So, my sister and mother gave them buffalo's milk. And they might continue to feed them buffalo's milk regularly.
It's difficult to find advice specific to buffalo milk, but I think it's likely the advice would be buffalo milk is not good for kittens, and if you need to supplement their diet, use kitten formula instead.
The advice when it comes to cow milk seems to agree that cow milk isn't good for kittens due to the high lactose content which will give them diarrhea, and possibly make them dehydrated. Plus cow's milk doesn't have the same nutritional balance as cat's milk, and therefore it's not nutritionally healthy for them either.
Buffalo milk has even more lactose than cow milk, and therefore would surely cause diarrhea even worse. I would guess that it also has the wrong nutritional balance since buffalo are so different from cats.
