Why on the Nick show back at barnyard do all cows male and female have udders?

You are right to notice that the cows in "Back at the Barnyard" have udders, regardless of their gender. This is a creative choice by the show's creators and is likely done for several reasons:

* Humorous effect: It creates a humorous contrast and reinforces the cartoonish and whimsical nature of the show.

* Simplified design: Giving all cows udders simplifies the character design and avoids needing separate designs for male and female cows.

* Audience appeal: Young children might not understand the biological differences between male and female cows, and this simplification makes the show more accessible.

Ultimately, it's important to remember that "Back at the Barnyard" is a cartoon and not a documentary. The show takes liberties with reality to create a fun and entertaining experience for its target audience.