Sow feed additive capable of improving immunity of piglets and use method of sow feed additive

The invention relates to the technical field of feed additives, in particular to a sow feed additive for improving piglet immunity and a use method. The additive consists of a capsule, and a core material of the capsule consists of the following raw materials in parts by weight: 60-80 parts of calcium carbonate, 10-20 parts of montmorillonite, 6-8 parts of fish bone meal, 0.2-0.4 part of multivitamins, 1-2 parts of composite organic acid, 3-5 parts of a composite conditioning component and 0.1-0.5 part of a microecological preparation, a wall material of the capsule is prepared from the following raw materials in parts by weight: 50-70 parts of absolute ethyl alcohol, 1-3 parts of lecithin, 2-6 parts of propylene glycol alginate and 5-10 parts of a compound flavoring agent, and the ratio of a core material to the wall material of the capsule is (0.03-0.08): 1. The additive can effectively increase the lactation yield of sows, promote healthy growth of piglets, improve intestinal health of the sows, regulate t