随着畜牧业生产的现代化,以品种为单位的杂交已经日益显得粗糙,笨重,进展缓慢,因此,改品种杂交为系间杂交势在必行。国外畜牧生产先进的国家,大力推行系间杂交。在品种形成的基础上,可以较快、较易的建立品系,不断选择新的理想的杂交组合。为了进一步提高新浦东鸡的早期生长速 With the modernization of animal husbandry, crossbreeds based on variety have become increasingly rough, bulky and slow to progress. Therefore, it is imperative to change the cross between varieties for crossbreeding. Countries with advanced livestock husbandry in foreign countries vigorously promote crossbreeding. Based on the formation of varieties, you can quickly and easily set up strains, continue to choose the ideal combination of new hybrids. In order to further improve the new Pudong chicken early growth rate