Who's Mooing?

Caillou and his family are leaving for a picnic in the country but the ride feels very long for Caillou, especially since he cannot play with his toy airplane because he might wake Rosie. When they stop at a gas station, Caillou spots some cows in a field next to a picnic area. The family decides to have the picnic there, where they have a close encounter with some cows.