Those poor suffering cattle
Credit the movie Cowboy with trying to show the western life as it really was, rather than just another shoot 'em up. My only complaint is that they drove those poor cattle over some of the bleakest terrain in the southwest, with scarcely enough grass around to support a prairie dog, let alone cows. And where was the water that cattle need? No streams, ponds, nothing. Wouldn't half the herd have died of starvation or thirst?
Reminds me of the opening scenes in The Searchers. Same thing. Big John's brother (?) has a ranch: cattle & a stock pond, but there isn't a sprig of grass to be seen for miles.