Just before the stampede the amount of shaving cream on Ed's face changes as the shots change.
As Mitch and Curly ride along side-by-side on their horses, Curly's cigarette goes from long to short and all lengths in between.
As Mitch walks up on Jeff and T.R. as they are harassing Bonnie, Jeff is standing with his right side to Mitch. When they switch cameras, Jeff has moved so his back it to Mitch.
After the cattle drive is over, Clay says, "Let's get some grub". Ira, Ben and Steve, Barry, Cookie, and Bonnie follow, in that order. But when they switch cameras, their order is Barry, Ira, Bonnie, Ben and Steve, and Cookie following Clay and Millie towards the house.
When Phil is holding the drunk cowboy at gunpoint, you can see bullets in the cylinder. But immediately after, and without any shots fired, the chamber is empty.
Incorrectly regarded as goof. Phil mentions that he had to work every weekend for a year to afford the trip. As a grocery store manager, he is in a salary position and required to work weekends anyways. However, given how his father-in-law owned the store and treated him terribly, he may be paid hourly and worked seven days a week for a year. Or he is salary, and worked seven days a week for a bonus.
The cow that gives birth is a steer - a castrated male.
The calving scene is a genetic impossibility. The "mother" is a mixed-breed beef cow, giving birth to a pure-bred Jersey dairy calf.
When the big thunderstorm begins, a shot of the sky is completely static. Revealing it likely to be a matte painting.
When Mitch is running right in front of a chasing white bull in Pamplona, it clearly is a stuntman.
During the stampede, when Mitch is up a tree, the metal fencing around the base of the tree to keep the cattle away is visible.
(at around 1h 30 mins) As Mitch, Phil, and Ed are herding the cows down the slope and into the river (when Ed is already midway across the river), if you look to the extreme left of the frame (in the DVD wide screen format), you can see a man at the base of the slope. He momentarily darts into frame and back out again.
When Cookie starts driving the wagon while drunk, you can clearly see someone in the wagon looking out from under Cookie's bench.
In the scene where Mitch is explaining how to use a VCR, shadows of film equipment are cast on the sides of the cows moving across the foreground.
When Mitch is at a New York airport, a background sign says LAX.
At the end of the film Mitch and family drive away from what is meant to be a New York airport, but in the very next shot (the closing shot) they are shown driving South across the (RFK) Triborough Bridge, which means they were heading *toward* the airports.
At the end of the movie, Ed Furillo says he wants to follow Admiral Byrd's route to the North Pole. He mixes up details of Admiral Robert Peary's North Pole voyage with Richard E. Byrd's South Pole expeditions.