Grandpa was showing Little Joh…

Grandpa was showing Little Johnny around the farm, and when they come to the corral, he explained, “That’s a bull and a cow, and he’s serving her.”
A little later on, he said,”That’s a stud and a mare, and he’s serving her too.”
That night at supper, after everyone was seated and grace was said, Grandma turned to Grandpa and said, “Will you please serve the turkey?”
Little Johnny jumped up and yelled “If he does I’m eating a hamburger!”