Jonathan talks about taking water samples in Zeke's and Val's presence. In the next scene, Zeke and Val see a truck coming along the bank of a body of water, and are confused why the truck is there. Using binoculars, Zeke discovers it's Jonathan taking water samples.
The horns on the car were from a Longhorn. Brahmas are short horned.
In the final scene in Purgatory the glass in the window, that is smashed by the car, is obviously "sugar" glass used for stunt work.
Bad guy in the car is shooting his gun into the air.
Wealthy ranchers don't make steaks from a bull; they make ground beef.