DUI on Horseback

A man in the SE has been charged with DUI a after riding his horse(slowly) through town and being sobriety tested. The officer who arrested him said a "vehicle" is anything that could be used to transport on streets and roadways...Maybe they were afraid the horse would be intoxicated by the fumes of the man, he tested 3 times the alcohol limit...What is this world coming too? Did these officers ever see Trigger? Many horses have carried many a drunk cowboy home-oops-I guess our man-date man drove cars when he received his 2 DUI´s, like shamey, can he ride a horse? I doubt it, he likes to milk the males...not ride them...