Also if you see a livestock truck on the road. Get away from it. Especially if its raining. ESPECIALLY if you are on a motorbike or driving a convertible. Animals dont stop pissing and shitting just because they are on the truck.
You want your vehicle shotgunned with a pig excrement slurry? Nah didnt think so.
I have a pet pig. If he’s free to bounce around on a ride, he’s going to fuck himself up and any animals near him. Pigs panic at a pin drop and they’re far heavier and more powerful than they look. They’re tightly confined when traveling for the same reasons horses are.
Tbh, I can’t think of any animal that should be completely loose during transport in any situation. Even a dog that loves riding in a car needs at least a safety harness.
Livestock? They’ll get hurt bad without restrictions on movement. They could be pets instead of food, and you’d still need them restrained during travel if you want them and the vehicle safe. But livestock that have never been (or can’t be) trained the way pets are, it’s exactly like you said, you want them to stay as still as possible without causing blood flow restrictions. It’s safer for them, for the vehicle, and for everyone else on the road.