Plant feed for improving heat stress resistance of calf and feeding method

The invention discloses a plant feed for improving heat stress resistance of calves and a feeding method. The plant feed comprises Allium mongolicum, soybean meal, wheat bran, corn, alfalfa and oat. During feeding, fresh Allium mongolicum is cut into segments, and the segments are mixed with concentrated feed corn, wheat bran and soybean meal. The alfalfa and the oat are fed in the morning and at night every day, and the daily feed intake of the alfalfa and the daily feed intake of the oat are 25-35% and 25-35% respectively according to the dry matter feed intake weight; dry substances including, by weight, 15%-20% of corn, 12%-16% of bran and 8%-12% of soybean meal are used as concentrated feed to attract and feed the Allium mongolicum sections at noon, the daily addition level of the Allium mongolicum is 300-800 mg/kg BW, and the Allium mongolicum freely drinks water. According to the invention, the plant feed additive is adopted, and the antioxidant capacity of the body is improved by changing the indexes