As mudhen said it had a lot to do with how the oxen had to eat. Cattle can grab a belly full of grass quick but then they MUST lay down to digest it over several hours. To do that they have to be awake. Graze out you ox late in the day and he just won't have time to digest his meal before he goes to sleep and he has to sleep or he won't go the next day as he's too tired.
A horse or mule can digest as they go.
Would you believe that years ago I sold as scrap iron a half keg of ox shoes that had been on the place forever. How many times have I figuratively kicked my dumb butt for doing that.
Still have the two sets of ox yokes though.
