I found it. It was Manet, not Monet, and it's not obvious that the cows are, indeed, a takeoff on The Picnic ("Le Dejeuner sur l'Herbe"* 1862-63.Oil on canvas, Musee d'Orsay, Paris .
*I love French - we say "picnic", they say "dinner on the grass".
What a hoot -- or should I say moo! Sort of a bovine version of the impressionist (Monet?) painting of the nude women (men clothed, of course) having a picnic on the grass. I wonder if this barn painting was as controversial. :)
