The Confederate Army used the same tables and Quartermasters forms as did the Union Army.
The daily allowance per animal was 14 pounds of hay, and 12 pounds of oats, corn or barley.
For the period October 27 through November 5, 1863 at Athens, Tenn., Col. J. W. Gillespie submitted a requisition, Form 32, for, I assume the Field & Staff of the 43rd Tennessee Infantry, CSA.
Horses, 11, mules 6, total number of animals 17, for 10 days, number of rations 170.
Daily Allowance to each animal, 12# Corn, 14# Hay.
Total allowance 2040# Corn, 2380# Hay.
Looking at it another way, 26# of forage per animal daily.
Mercer's 225 animal 6 gun battery would require 175,500# corn/hay a month, 3 tons daily!
An Infantry regiment, in addition to the horses of their officers, for, say 30 wagons, 4 horses each, require another 1.5 Tons daily.