皮南牛适宜级进杂交代数的研究

本研究选择12月龄皮南杂交（皮埃蒙特牛×本地南阳牛）公牛F1、F2、F3各30头，在7、8、9月份进行统一育肥试验，探讨夏季湿热气候对不同杂交后代生长发育状况的影响，以寻找皮埃蒙特牛与南阳本地黄牛适宜的级进杂交代数。结果表明，级进F2杂交个体比F1和F3更能适应当地夏季较为强烈的湿热气候，并保持优良的产肉性能，故杂交选育宜在F2代基础上进行。

Research on the Suitable Grading Crosshreeding Generation of PiedmontesexNanyang Cattle

In order to research the effect of summer hot humid climate on the production performance of P×N crossbreeding cattle, and select suitable grading crossbreeding gencration, 30 heads of F1, F2, F3 erossbreding P×N cattle were selected to fatten in June, July and August. The results showed that cross breeding generation of F2 individual was more adapt to the local climate, and kept excellent production performance. So crossbreeding of P×N cattle should be performed on the basis of F2 generation.