Cattle in cattle trucks smell pretty barnyard-y too. One afternoon in Omaha I had the privilege of passing two semis hauling live cattle in well ventilated trailers. This is what steak smells like before you kill it....
Yes cattle trucks in Kansas are even worse than the feed yards. If you are following one, you often see manure falling out the back.
Other states seem to make them keep their trucks cleaner as I have seen cattle trucks or trailers here in Florida and there is no smell at all.
Cattle trucks? I risk speeding fines to make sure that I stay in front of them.
Get behind a semi loaded with slaughter house offal (usually covered by a tarp)and the stench is nauseating.