I raise cattle in the northwest of Durango, near Sinaloa and Chihuahua (Mexico).
We got a pretty hot climate, and I think that those cows and most of mine look pretty much the same.
How big is the terrain? Are you still feeding them something? We already have left them to roam around the ranch, but some of our neighbors aren't so lucky and still are feeding them.
Since the Sonoran Desert runs through AZ, I'm figuring you might have it just a little bit harder than us.
We have been using Angus/Brangus for quite some time now, and a couple of years ago we started to put some Charolais bulls into the mix with nice results.
My best advice is to always have water near by, hopefully you get a river; and use rotational grazing.
All that being said, I think your cattle is in good shape considering the terrain, hope you can post some before/after pics when the raining season is over.