Your state dept of transportation, or equivalent, should be able to give you listing of vehicle and trailer regs. states you will pass through require at their check places. Your statewide cattlemen organizations should be able to give you listing of cattle reg.s and possibly even of places such as the auction barns or others to unload cattle to rest, eat, and drink.
Maybe this is overkill for the miles you will cover with the cattle loaded, but having in mind all that could affect the cattle health puts you ahead of critics who may notice cattle they 'feel' are suffering at stops you make, not to omit hiway police!
One member of my family did have an opportunity to help out a trucker on a LONG haul who had a critter down in his potload last week. It would not have lasted long in the conditions, had they not corrected the load dispersion a little.
Best wishes for a successful trip.
mrj