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.]
Continuity mistake: When Marlboro Man rides a wheelie next to the motorcycle cop, the bike goes from having wide glide forks to a narrow glide setup.
Continuity mistake: After a passing train disturbs the Mousekewitz's home and extinguishes their candle, Papa strikes a match and lights it up. He tosses the match somewhere offscreen, but one shot later it appears right in front of his feet. (00:04:55)