Inspired by a teacher’s suggestion and weary of the udder sameness of a dairy farmer’s year, young Manny impulsively bustles his 500 cows onto buses for an end-of-school excursion to Niagara Falls. Anyone who’s taken a field trip with large groups of third-graders will know what to expect. Reluctant at first, the bovine brigade soon gets into the spirit of things, laughing hysterically at silly verses of “Old MacDonald,” horsing around (so to speak) on the buses and piling out at a roadside stop for snacks and sodas. The last activity results in a massive cowtastrophe, as the long ride ends next to “the world’s largest faucet,” and not even Niagara’s toilet facilities turn out to be quite up to handling 500 cross-legged vacationers at once. Becker illustrates the outing in light, sketchy views of rambunctious revelers thundering hither and yon on two legs, chattering and trading hilarious comments. Further disaster looms after the herd is let loose in the gift shop, but all ends happily with a smooooooth ride back to home pastures. Easily the most memorable ruminant retreat since David Kirby and Allen Woodman’s The Cows Are Going To Paris (1991), illustrated by Chris Demarest. (Picture book. 6-8)