the Berasit Hebrew Dictionary

פרש

'peres' is traditionally translated to mean one of several widely differing meanings, including “horse”, “spread”, “dung”.

It is possible that the “horse” meaning is derived from the fact that one “spreads” their legs to mount a horse, and that the speed of riding a horse enables the rider to “spread out” over a large range of land.

The “dung” meaning may refer to the use of horse dung as manure which is spread upon a garden to increase its growth and yield.