CollegeofAnimalScienceandTechnology;
ShandongAgriculturalUniversity;
Tai'an;
China;
CollegeofAnimalScienceandTechnology;
ShandongAgricultural//Correspondingto:Dr.ZhongxiangNiu;
CollegeofAnimalScienceandTechnology;
ShandongAgriculturalUniversity;
Tai'an271018;
China.;