The 7th and 30th Dragoon Regiments from the 6th Heavy Cavalry Division were engaged at the Battle of Vyazma on 3 November 1812. Doumerc's division joined the remnants of the main army in time to fight at the Battle of Berezina. From 26 to 28 November, Napoleon's retreating army streamed across the ice-choked Berezina River on makeshift bridges. On the 28th, a force of 30,000 Russians tried to advance up the west bank to cut Napoleon's line of retreat but was stopped in a desperate struggle by 14,000 French troops. During the struggle, Marshal Michel Ney ordered Doumerc's cuirassiers to charge. The heavy cavalrymen hurled back the Russians, capturing 2,000 men. The III Cavalry Corps units involved were the 4th, 7th, and 14th Cuirassier Regiments. Casualties were horrific during the retreat and included General Denis Étienne Seron who vanished without a trace in November. In February 1812, the 8th "Chasseurs-à-Cheval" of Chastel's division left Italy 800 strong and a year later there were only 75 survivors. In 1813, Napoleon managed to fill the ranks of his infantry by conscripting under-aged youths and his arsenals were able to cast more cannons to replace the one thousand guns that were lost. But the loss of over 200,000 horses and trained horsemen in Russia crippled his ability to field an effective cavalry arm in the next campaign.