Typical signs of PRDC include body temperature rising,cough,dyspnea, low feed effect and low growth rate, which finally caused low growthperformance and high death rate.

• PRDC最典型的症状包括体温升高、呼吸困难、咳嗽、饲料转化率降低以及生长缓慢和发育不均匀、死亡率升高等。