Though I do think Hitler was either mislead, or choose to believe his forces were greater than they where. For example Barbarossa used 750,000 horses.
German Army entered World War II with 514,000 horses, and over the course of the war employed, in total, 2.75 million horses and mules; average number of horses in the Army reached 1.1 million.
Most of these horses were employed by foot infantry and horse-drawn artillery troops that formed the bulk of the German Army throughout the war. Of 264 divisions active in November 1944, only 42 were armored or mechanized (November 1943: 52 of 322)