I believe that cultivated oats are grains that are still growing. I know that when I was growing up and the cows or horses got out into a growing field, everyone panicked. If the animal got too much of the fresh grain or alfalfa it fermented in the second stomach. They are unable to burp out the gas so the vet would have to come out and ....well, it was pretty graphic. If the pressure was not released, the animal died. I have seen bloated cows and horses, and it's not a pretty sight. Once the grain or hay is dried, it's not a problem.