The subject of the present invention is to provide a method for improving the sperm function of male livestock and increasing the fertilization rate of livestock. When 5-aminoacetoxypropionic acid is added to feed and administered to male livestock, the rate of abnormality of sperm from the administered male livestock is reduced.本發明之課題在於提供一種用以改善雄性家畜之精子之機能,提高家畜之受精率之方法。於將5-胺基乙醯丙酸添加至飼料並向雄性家畜投予之情形時,來自被投予之雄性家畜之精子之畸形率減少。