Yotsuba&! manga volume 7 features story and art by Kiyohiko Azuma.

Mooooo...! MOOOO...! Cows are neato! It's fun pretending to be a cow! And milk comes from cows, so I bet they're real nice too. 'Cos milk is super-yummy, right?! Yotsuba thinks so! And milk comes in lotsa flavors, so cows must come in different flavors too. How else is there white milk and coffee milk and chocolate milk?! Then there's the black and white cows, they've gotta make a super-secret special flavor, huh?! Yotsuba wants to know! Let's go ask the cows at the ranch, Daddy! Come on!