Let us not haste to judge here.
Maybe the coyotes in Michigan are real big, and have developed horns and cloven hoofs?
Personally, i think this could be the result of a misprint in a childrens book about farm animals: "The dog says "woof", the cat says "meow", and the coyote says "moo".
Remeber those toys, the one where you would pull the string and the arrow in the center of the toy would point to an animal and say The dog goes woof woof, the pig goes oink oink, etc? When I was little I had a hand me down from my brother and it would always put the wrong sound with the animal. The rooster goes hee haw, hee haw! LOL! It's a wonder i'm not all messed up now, lol.