Influence of restricted feeding with nostril plugger on fertility rate of male broiler breeders肉用种公鸡鼻孔插限饲器后对受精率的影响
Rectifying nipple inversion by using crescent valve plugger and continual traction nipple with home-made external fixtu新月形瓣充填加自制外固定架牵引矫正乳头内陷