Excuses for a February Party

This from the Wisconsin Almanac, under "Excuses for a February Party":
[Feb.]18 Elm Farm Ollie Day.
On February 18 the Elm Farm Ollie Fan Club of Madison honors the anniversary of the first time a cow flew in an airplane. As part of the celebration of the St. Louis International Air Exposition in 1930, Elm Farm Ollie was milked in flight, then little containers of her milk were parachuted over the city.