Efficacy of bivalent vaccines of porcine circovirus type 2 and Mycoplasma hyopneumoniae in specific pathogen-free pigs challenged with porcine circovirus type 2d

猪圆环病毒 2 型和猪肺炎支原体双价疫苗对感染猪圆环病毒 2d 型的无特定病原体猪的免疫效果