PROBLEM TO BE SOLVED: To find new usage regarding an iron and semiconductor alloy such as a ferrosilicon.SOLUTION: A method for promoting and activating growth of animals includes installing the iron and semiconductor alloy made of 78-98 wt.% of iron, 1-10 wt.% of the semiconductor, and an inevitable impurity, made into steel by adding the semiconductor to molten steel of the iron, and molded in a plate-like by hot rolling, in the vicinity of an animal, and irradiating the alloy with sunlight or a white light so that the vibration of the semiconductor is intensified and a vibration electromagnetic wave is enhanced, and thereby, the growth of the animals in the vicinity of the alloy is promoted and activated.