It designates that conception Characteristic of the semen after the freezing retaining is improved by improving the straw for former artificial insemination, as topic. As settlement means, introducing isolation formation into the straw for artificial insemination, it separates formation, as the semen retention formation which consists of the aqueous solution which on the one hand includes the semen and the resistance freezing medicine and the dilution formation which the resistance freezing medicine is not included anymore on the one hand included, it produces the straw for freezing, the tris (the hydroxymethyl amino methane), it depends on using the dilution liquid which consists of the aqueous solution which includes citric acid, glucose and sodium chloride in dilution formation.従来の人工授精用ストローの改良を行うことにより、凍結保存後の精液の受胎性を改善することを課題とする。解決手段として、人工授精用ストロー内に隔離層を導入して層を分離し、一方に精液と耐凍剤を含む水溶液からなる精液保存層、もう一方に耐凍剤を含まない希釈層を含むように凍結用ストローを作製し、希釈層にトリス(ヒドロキシメチルアミノメタン)、クエン酸、グルコース、塩化ナトリウムを含む水溶液からなる希釈液を用いることによる。
