I found this bit of info on the 7th Pennsylvania Cavalry Horses in the National Archives, is quite interesting of what a Cavalry unit did..
There Should Be A Memorial For Horses
The Horses of The Seventh Penna. Cavalry
During the Atlanta campaign, the 7th Pennsylvania Cavalry was heavily engaged in scouting and skirmishing with the rebels. The men suffered daily and also their horses. Here is a report taken from the monthly regimental reports found in the National Archives in Washington D.C. about how the horses suffered.
HQ 7th Penna. Cav.
Near Blakes Mills, Ga
Sept. 13, 1864
Capt. R. Burns
1st Brig. 2nd Cav. Div.
Sir, I have the honor to report that the 7th Reg. Penna Vol. Cav. started on the 30th day of April with 919 horses, fresh from the corral at Nashville and unused to military duty. The majority were young horses not aged. 300 of the enlisted men were raw recruits some had never been on a horse before. They entered the service and without drill. We travelled along the line of the Nashville and Chat. R. Rd. for 48 consecutive hours the horses were without feed and travellled 43 miles passing a depot from which forage was carried at least eight miles. May 5 we marched 23 miles without feed. At Ned City rec'd 28 Ibs of corn for 3 days to be carried upon the horses in addition to 5 days rations and travelled 33 miles crossing at Raccoon Sand and a spur of Lookout Mtn. The young horses commenced to lag. A few were abandoned and the hearty and strong horses were fatigued. The Col. Wm. B. Sipes then commanding instituted morning inspections compelling every man to groom his horse and graze when an opportunity occur ed.
From the 16th of May to the 19th the horses had no feed except the leaves and short grass to be found in the hills around Andersonville, Ga. During this time we travelled 35 miles. The last 5 from Kingston to the free badge was travelled at a gallop causing the horses to give out by the dozen (as figures will prove.) That night we rec'd the first forage the horses had for 3 days. Out of 72 hours the horses were under saddle for 60 hours and receiving all the attention the men were able to give. On the morning of May 22 the comdg. officer of companies reported the loss of 76 horses as died of starvation and abandoned. Upon investigation the vet. surgeon corroborated the statement and pronounced 43 were unserviceable and unfit to travel. Up to this point the horses were groomed as regularly as circumstances would permit. Out of the 43 horses left to recuperate 15 were returned to the command Aug. 5/64. From May 26 to June 2 (7days) the horses were without and actually starved. One battalion (the 3rd) lost in action trying to procure forage 33 horses and 101 were starved to death and compelled to be abandoned. A detail commanded by Capt. Garrett travelled 30 miles and returned without forage. June 11 and 12 no forage. A detachment commanded by Capt. Newlin travelled 26 miles returning with 1 qt. for a horse. From July 13 to 18 rec'd half forage. From 19 to 22 no forage. But stuble field to graze in. June 20 lost in 26 horses. From June 23 to July 17 rec'd 1/2 rations. July 18 and 19 no forage. From July 27 to 30 forage on the country for 20 miles around Stone Mountain. All was hacked upon the withers of the horses doing as much harm to the horses as the feed did good causing sore backs. From Aug. 1 to Aug. 15 the command was 5 miles away from the horses. 4 horses were groomed by 1 man cause consequently they were not as well taken care of as the ride would give them. For 48 hurs they were without feed.
Aug 15 and 16 rec'd 1 qt. per head and travelled 24 miles over a country devastated by the army. Aug 17 and 18 rec'd 1 pint feed from 3d Div. Aug 19, 20, 21,22,23, and 24 travelled 120 miles feeding but once on green corn. 1/2 ration of forage was issued to Sept. 9 Sept. 9 ,10,11 no feed and no grazing. The stock rec'd no salt or hay during the campaign. Lost in action Aug. 20 112 horses.
Started with 919 horses
captured 42 horses
total 961 horses
and died 230 horses
captured 171 horses
Total Lost 401 horses
the field 560 horses
From the Regimental Records Book