We've hauled cattle from Idaho to Utah, both directions, on many occasions. It's a minimum 8 hour drive in a car - about 10-11 hours when hauling. We usually stop for a meal or two and try to park the trailer in shade. The trailer is deeply bedded with straw and the cattle tend to lie down and rest nearly all of the trip. I think parking for a little while gives the cattle time to rest without the motion of the trailer, which is nice, but not absolutely necessary. We have driven straight through more than once, with only gas & fast food stops, and the cattle did great. As much as we try to avoid giving antibiotics, we do give a shot of antibiotic before a long trip.