Yes, the 1st and 3rd MO Cav were dismounted in Des Arc, AR before crossing the river in 62. They fought as infantry for the rest if the war. The 1st and 3rd were consolidated in 63 after Vicksburg to form the 1st-3rd MO Cav dismounted, and fought east of the river in the MO Brigade until captured at Fort Blakeley in 65.