The Big Bang Theory Season 9, Episode 8

And probably half that if I break out the old cow eyes.

The Big Bang Theory Season 5, Episode 20

Except they leave room for a cow. (chuckles)

The Big Bang Theory Season 6, Episode 9

How much longer is he gonna milk that cow?

The Big Bang Theory Season 4, Episode 9

Whoops! Can't go any further, there's a sacred cow in my way.

The Big Bang Theory Season 4, Episode 9

Tell your boyfriend to cool it with the cow jokes.