It most parts of the US, it is illegal to have cattle operate motorcycles. Their hooves have problems with the controls.
Also, for states with helmet laws, there is another problem - no one makes a decent DOT approved helmet for cattle. Again, the hoof thing; they can't fasten the chin straps.
There is also a legal issue, even if cattle had pockets to carry drivers licenses the written portion of the test is very difficult for them.
Finally, and perhaps most importantly, cattle don't have much concept of rules of the road even as pedestrians. They will stand in herds in the middle of the road, block traffic, wander down the wrong side of the street. You really shouldn't be giving motorcycles to livestock just as a general rule.