As previously posted, at least two Federal units formed in Boone County went by the name "Tigers"--the Columbia Tigers, which was formed in early October 1864 and ultimately was the namesake for the University of Missouri mascot, and the Boone County Tigers, which was formed in 1865 and apparently borrowed the same name from the the Columbia Tigers. The Boone County Tigers was formally known as the Boone County Missouri Militia, or Captain Cook's Company, Boone County Missouri Militia.
From the Aug. 4, 1865 Columbia Statesman (reprinted on p. 478 of the History of Boone County)--
CAPT. COOK'S COMPANY RELIEVED --- THE MILITARY OCCUPATION OF COLUMBIA IS SUMMARIZED.
On Friday morning, December 21, 1861, Lieut.-Colonel Morse, with a detachment of the 22d Missouri Infantry, Col. J.D. Foster, left this place for Centralia, the editor of this paper and Colonel Francis T. Russell accompanying them for considerations of personal safety. Columbia was without Federal troops for one week --- until Friday evening, December 27, 1861, when Capt. John Welker, of Birge's Sharpshooters, Infantry, arrived with about 200 men and took up quarters in the State University. On Sunday night, December 29th, Capt. Welker left for Sturgeon, and Columbia was again without Federal troops unitl the following evening, Monday, December 30, when Col. John M. Glover, 3d Missouri Cavalry accompanied by Col. Birge, came in with 230 men and left the following evening, December 31. From Tuesday to Thursday evening, January 2d, 1862, Columbia was without Union troops, when Col. Merrill [2nd Mo. Cav.] arrived with a large protion of his regiment. Not a day since December 31, 1861 --- January 2, 1862 --- until Tuesday last, August 1, 1865, three years and seven months, has our town been without the presence of Union soldiers of some kind. On Monday, Capt. Cook's company of Boone county militia was relieved from duty, leaving "Camp Switzler" to take care of itself. There is not a Union soldier on duty in the county; and what is better still, no necessity for their services, for all is peace and safety once more. Let us thank God, take courage, and move vigorously onward!