The cow says “Moooo.” What’s better than listening to you
make animal noises? Nothing. So far, you’ve mastered the lion,
tiger, dinosaur (all roar), cow, horse, cat, dog, sheep and
elephant. We are working on the rooster. 
Home » Daily Memories » Moo
My son is starting to make animal sounds. He’s currently saying “moo” every time he sees a cow.
Chris Hall
The Adventures of Jaydon and Daddy
http://JaydonAndDaddy.com
I love those first words! It is so fun to watch them discover new things.