The theme is "Memoories In The Making" as in Memories, but in relation to a cow mooing. Sorry for the confusion there. It is ridiculous.
Our Alaska State Fair had a similar theme in 2018 ("Memories in the Making"), minus the "moo" element, which actually gives you a little moooore to work with (ugh, I know, but I couldn't resist). It was pretty difficult to come up with visuals, but my clever son thought up two winners, which he used to earn the big prizes in the "VegHeads" contests (involving making a display of some sort out of produce). Maybe his ideas will give you some of your own.
The first used a big gnarly potato, with the eyes having sprouted around one end in a halo that reminded him of a grandpa. He set that one up to look like it was sitting in a chair (cut-up pepper), holding a book that it was reading to a bunch of little new potatoes, like in a story time.
The other was a squash decorated to look like a diva singing "Memories," lettuce leaf ball gown and all.
How about a cow and a rabbit singing a "Memories" duet? Or a mama cow reading to a bunch of bunnies, or looking at a scrapbook together? Or a cow taking photos of rabbits, or vice versa? Or a cow remembering/dreaming (a la speech bubble) of prize-winning rabbits?