Yes, cows can eat mushrooms with no issues at all.
The cows in our field prefer young hawthorn shoots, reeds, ivy, and anything that is easy food for them in my garden.
In its season, you might find yourself struggling to get to the mushrooms before cattle get to them. I have found out that they love puffballs and mushrooms.
ALSO SEE: How to Keep Cows from eating Deer Corn
Do Cows Eat Mushrooms?
Sure! Cows eat edible mushrooms. You can cut, cook, roast or fry them for them.
Mushrooms growing in the wild is a good indicator of fertile soil. Having that complex web of microorganisms doing their secret hidden work under your feet, fixing carbon and making nutrients available for grass means you already have the eco-system for successful farming.
Healthy soil full of fungi leads right through to healthy grass, healthy cattle and more healthy beef on your plate. As our beef cattle only eat grass and other plants found in the pasture and hedges (and the odd mushroom) this is massively important.