Continuity mistake: There is no way the cow (a Hereford I think) could have given birth to that calf (a Jersey or something like that). [The mom is a mixed-breed BEEF cow, the calf a purebred Jersey DAIRY calf. An amazing feat of animal husbandry.]
Other mistake: In the opening scene, Mitch receives his birthday phone call from his parents. As he gets out of bed, the pillow case has perfectly ironed fold marks even though he has just slept the night in the bed.
Visible crew/equipment: During the scene where Cookie is drunk and takes off in the covered wagon, if you look under Cookie's seat you can see a person in a dark shirt inside the wagon. It can't be one of the movie characters because when he heads towards the cliff, he's the only one who jumps out of the wagon and in the next scene only the horses are buried.
Continuity mistake: When Mitch is getting ready to grind the coffee beans, in the wide shot, the grinder is about 2 feet away from his body. When they cut to the close-up, it's about 6 inches from his body.
Continuity mistake: When the group buries Curly, the viewer can see a bunch of flowers stuck on the 'grave,' just a few inches away from the makeshift cross. After the group moves on and Mitch says his final goodbye to Curly, there is a brief overhead shot of the grave and the flowers are now in the center of the mound instead of by the cross.
Plot hole: Norman, the orphaned new-born calf, could not have survived more than a few days after birth unless he was adopted by a foster-mother cow. The cattle were not dairy cows, and it's obvious the "cowboys" are not providing milk or other sustenance for Norman. Even if he had lived, he would be extremely weak and emaciated and physically unable to run with the herd.
Visible crew/equipment: In the stampede scene, just as the cattle are coming over the hill towards Curly and his revolver, a helicopter blade (from the crew's helicopter) is seen rising just behind the cattle, on the left half of the screen. (Widescreen DVD.)