Civil war batteries were manned by six men per cannon, who performed an elaborate dance to load and fire. Their duties were

1) Sponge and ram
2) Receive charge and round and place in muzzle
3) Service primer vent - very important to prevent a misfire
4) Prime and yank lanyard on command
5) Transfer charge and round from the limber to No. 2
6) Gunner - sight gun and command fire

The artillery horses were either tied to the limber or held fast by the driver lying on the ground with the reins of his team (two horses) in hand, some distance back of the piece. The driver's chief skill was facility with horses, particularly keeping them calm during the chaos of battle.

Artillery horses were buried when possible, with soldierly honors.

Grant, called a "butcher" by Northern newspapers for the appalling casualties his army took, was very protective of horses - he once had a man tied to a tree for three days for mistreating a horse.

Here is an actual photo of a battery [link|http://www.archives.gov/digital_classroom/lessons/brady_photographs/images/fredericksburg_battery.gif|in action] at Fredericksburg.