"Bill Haponski" <haponski@seacove.net> was a former S3 and XO ofthe Blackhorse when he assumed command of the 1/4 Cav in the Spring of 1969.  He wrote: 

The Quarter Horse worked with the Blackhorse cavalry on many occasions in Vietnam

FIRE SUPPORT FOR TASK FORCE HAPONSKI
ATTACK INTO MICHELIN PLANTATION, 30 MARCH 1969

Summary:

Artillery - In excess of 1100 rounds high explosive, 105mm and 155mm, over 4 hours total firing time from 0710 - 1700 hours, either on base camps, LZ prep, or in close support of troops in contact:: B/1-4, C/1-4, D/1-11 ACR, D/1-4 ARPs.

Air - 11 strikes, 2 fighter bombers each, 24 tons of bombs, 1600 rounds 20mm cannon, 28 cannisters of napalm, from 0836 - 1732 hours, on base camps, LZ prep, close support of troops in contact.

Air cav - Recurring activity from daylight until dark, numerous gun ship and light fire team runs on base camps, enemy troops sighted, support of troops in contact, 2 ARP insertions and extractions.

Following are the records of support: artillery, air, air cav. During the night of 29/30 March, the task force is in or near Fire Support Base Doc, XT613521, at the eastern edge of the Michelin Plantation. Direct artillery
support comes mainly from two units of 2d Battalion, 33d Artillery located in FSB Doc. They are D/1-5 Arty, a battery of 6 tubes of 105 mm, and a platoon of 2 tubes of B/8-6 Arty. A/2-33 Arty (at FSB Picardy?) also supports, as do a few tubes, probably 4 to 6, of 81mm mortar at Doc. Air support is from unidentified American units, probably Air Force out of Bien Hoa AFB, and also (probably) an unidentified Vietnamese air unit. F100s, F4Cs, and A37s fly the missions. Gun ship support is from D Troop (Air) 1-4 Cavalry under operational control of the task force. Records from 1st Inf Div history team, 1st Inf Div G-3, 2-33 Arty Bn, 3d Brigade of 1st Inf Div, and 1-4 Cavalry were used to compile the following sequence of support. Records yet to be obtained are:: Air Force, additional 1st Div Arty, 25th Div Arty (which may have supported out of Dau Tieng), 1st Avn Bn (for additional input on D/1-4 participation).