通常牧草的品种和生态型的耐冻性程度与品种育成地和收集场所冬季的寒冷性密切相关,一般产于寒冷地区的品种其抗寒耐冻性较高。阿部曾对在日本育成或从国外引入的24个品种的鸡脚草进行了耐冻性与育成地1月份平均气温间关系的研究,确认其间具密切的相关性(r=-0.894)。本研究以在北海道育成的和取自北海道各地的多个鸡 Generally, the degree of frost resistance of the grass species and the ecological type is closely related to the coldness in winter of breeding areas and gathering places, and the varieties generally produced in cold areas have higher cold and freeze resistance. Abe studied the relationship between frost resistance and average temperature in January of 24 hemp grasses which were bred in Japan or imported from abroad and confirmed that there was a close correlation between them (r = -0.894). This study is based on a number of chickens bred in Hokkaido and taken from all over Hokkaido