I've bid on books on some auction sites older than that but they end up being too rich for my blood!
This document is dated 1925 but is revised so it probably was from an earlier work. It is titled Swine Feeding.
It covers quite a bit of topics such as:
Skim milk and buttermilk
Linseed oil meal
Soy bean oil meal
It even contains a table that shows several different types of pasture crops for pigs.