PROBLEM TO BE SOLVED: To provide a freezing preservation liquid and a freezing preservation method of a bovine reproductive cell such as bovine sperm having low cell cytotoxicity.SOLUTION: A freezing preservation liquid of a bovine sperm contains a structural unit represented by a formula (I) and a structural unit represented by formula (II), and contains 0.3-0.9 w/w% of an amphoteric polyelectrolyte (antifreeze polyamino acid) having a ratio of a structural unit represented by formula (II) of 50-99 mol% and 2-4 w/w% of glycerin. In the freezing preservation liquid, the above described antifreeze polyamino acid and glycerine are added to a Dulbecco's modified eagle's medium (DMEM), MEM medium (MEM) of eagle, other culture liquid for cell or other physiologic liquid, a pH is adjusted to 7.0-8.0, and 5-20 w/w% of a liquid derived from bovine semen is added to the freezing preservation liquid.SELECTED DRAWING: None【課題】細胞毒性の低い牛精子等の牛生殖細胞の凍結保存液及び凍結保存方法の提供。【解決手段】式(I)で示される構成単位及び式(II)で示される構成単位を含み、式(II)で示される構成単位の割合が50～99モル％である両性高分子電解質（不凍ポリアミノ酸）0.3～0.9w/w％と、グリセリン2～4w/w％とを含む、ウシ精子の凍結保存液。更にダルベッコ改変培地（ＤＭＥＭ）、イーグルのＭＥＭ培地（ＭＥＭ）、その他の細胞用培養液、又は、その他の生理溶液に、前記不凍ポリアミノ酸及びグリセリンが添加されるとともに、ｐＨが７．０～８．０に調整され、牛精液に由来する液体を５～２０ｗ／ｗ％になる様に添加する凍結保存液。【選択図】なし
