Respiratory coccidiosis (Cryptosporidium baileyi) among northern Georgia broilers in one company.

Cryptosporidium baileyi causes respiratory disease in chickens. The purposes of this prospective study were to determine the incidence of C. baileyi tracheitis among broilers in a commercial setting, and the relationship between C. baileyi tracheitis and production performance parameters. All samples came from 56 farms that grow broilers for one company in northern Georgia. Tracheas were collected and examined with a light microscope and cultured for viruses and bacteria. Overall, 23 of 56 (41%) broiler flocks had C. baileyi tracheitis. Parasitism rates among C. baileyi-infected flocks ranged from a low of 10% to a high of 60%. Cryptosporidium baileyi tracheitis was very highly correlated (rho = 0.81, n = 56, P < 0.00001) to severity of tracheitis, negatively correlated (rho = -0.27, n = 56, P < 0.04) with average body weight, and correlated with airsacculitis (rho = 0.30, n = 56, P < 0.03) and condemnations (rho = 0.27, n = 56, P < 0.05). The present study indicates that C. baileyi infection rates are high, and the role that this parasite plays in the pathogenesis of respiratory disease and production losses could be unexpectedly large.