This eventually brought the entire training program down. In 1941, replacements were produced by Replacement Training Centers (RTCs). As new divisions were mobilized, they took their manpower directly from reception centers. The RTCs provided replacements for filler, and were organized to provide replacements in the proportion of units in the army. Army Ground Forces was responsible for training replacements for the four statutory arms (infantry, cavalry, field and coast artillery) and the three new pseudo-arms (armor, antiaircraft artillery, and tank destroyer). Replacements for the other arms and services were handled by the Army Service Forces. Casualties in combat units, particularly infantry units, exceeded the capacity of the RTCs to replace them. By February 1944, some 35,249 men had been taken from combat units in training for use as replacements; another 29,521 had been transferred from low priority units to fill up units preparing to move overseas. Between April and September 1944, as casualties in Normandy began to bite, some 91,747 men were stripped from twenty-two divisions in the United States. Maintaining 700,000 men in infantry units required 1,800,000 men in the infantry arm by April 1945. Over 1,000,000 replacements were shipped between September 1943 and August 1945, of whom 82% were infantry. Volunteers for the infantry were accepted from other arms and services. By 1944, all new inductees were being sent to RTCs, where they were trained for 13 to 17 weeks before being sent to combat units. As casualties mounted, a massive comb-out began as the Army Ground Forces struggled to provide replacements. Personnel from non-combat assignments were pulled from duty, hastily trained, and then reassigned to units as combat infantry replacements.