Big Buffalo  says
The first thing that a buffalo will ever eat is mother's MILK. The buffalo calf will soon start tasting grass and anything else that it can get in its mouth. Before long, it is eating grass just like its mother
For 8 or 9 months, buffalo mother will still give the baby her milk. Then she will "wean" the calf. That means she will tell him he is too big for milk and it is time for him to eat like a big buffalo.....on just grass.
It is amazing, but the only food that a buffalo needs is GRASS.
In the winter when the grass does not grow, the buffalo eats hay,
which is really just dried grass