It's actually a very old joke. "Donna" is probably an employee of the station, and this is a Publicity stunt... which clearly worked.
Interesting theory!
DJ: Thank you for calling WSCK.
Rarity: Love you guys! My question is how come in all the years I've slowed down at the Caution: Kids Crossing sign, I've never seen a goat? The final straw happened yesterday when my niece wanted to see a goat, so we jumped into the car and went to said site, all the while singing Mary Had a Little Lamb and that Doe a Deer song, hoping that would bring out the goats, but no joy. We did see a wolf, though. You don't think...
DJ: Are you related to Donna?
Rarity: Click!