Cows can easily walk down stairs.
Did you know that you can lead a cow up steps but not down? It has to do with weight distribution. Imagine a cow walking up stairs. The weight is towards the rear and when the knees bend they are pointing up. Now imagine the same cow going down stairs. The weight of the cow is now distributed to the front of the cow. Their knees are pointed down and they need to rely on faith that the next step is within landing distance or they will tumble down.
Cows can walk down stairs as long as the steps are shallow enough. Some dairy sheds have stairs for the cows to walk down if the shed is on slanted ground.