Can Cows Walk Down Stairs?
The claim that a cow can go upstairs but cannot come down is an overstatement. Cows may hesitate on steep, narrow stairs because the geometry is unfamiliar, their hooves are not suited to human stair dimensions, and judging the next step can be difficult. But that does not make descent physically impossible. Human stairs are often steep and short for a large animal; the individual animal and stair design matter.
Cattle should not be forced to try unsafe stairs: a fall can injure them. A more accurate statement is that cattle often avoid steep stairs and may be unsafe on them, not that they are anatomically incapable of descending.