They are at the 35th annual Midwest Horse Fair at the Alliant Energy Center grounds in Madison from Friday through Sunday.
The world's tallest horse is Big Jake, who lives on Smokey Hollow Farm near Poynette, Wis. The Belgian gelding is the Guinness World Record-holder for world's tallest living horse at one quarter inch short of 6-feet, 11 inches. He weighs about 2,600 pounds.
The world's tallest donkey is Romulus, who is 5 feet, 8 inches - five inches taller than the old record holder. His brother, Remus, is just 2 inches shorter and he will also be there. They are from Red Oak, Texas.
More than 50,000 people are expected to attend.