Why would baby bison die shortly after birth? Bison are native to the plains but they were born in midwest.?

Question

Could it be the grass they are feeding on with the size of the herd? Could it be the air temperature at the time they are born?

Answer 1

There are so many reasons that newborns in the animal world die, it is impossible to know with out a complete investigation of the situation.

It could be pollution in the grass, as you suggest, and nature has many other ways of getting rid of the unfit, as you have stated, so it could be.