Chronic Respiratory Disease (C.R.D.)

24.1.5 Chronic Respiratory Disease (C.R.D.)

Chronic respiratory disease is an egg-transmitted disease caused by an organism called “Mycoplasma gallisepticum. Moving, overcrowding, or stressing chickens in any way may trigger an outbreak of CRD. The disease is complex because three or more conditions are needed for the disease to develop. One condition is the presence of mycoplasma organisms. The second condition is stress. The third condition is presence of another bacteria, such as E. coli.

Symptoms:

 Discharge from the eyes or nostrils.

 Difficult breathing.

 Lack of appetite for feed and water.

 Listless and appear chilled.

 Failure to grow properly.

Postmortem findings:

 Thick, yellow pus (cheese-like) around heart, in lungs and air sacs.

 Trachea or wind pipe is inflamed (red in color).

 Sinuses inflamed (reddened in color) and contain mucus.

Diagnosis:

 Based on symptoms.

Treatment:

 Antibiotics  Tylosin injections (the best choice, if available and affordable).

 Tetracycline in feed or water.

 Penicillin injections.

 Erythromycin or Furazolidone.

Control:

 For broilers: raise only one age group at a time (called an “all-in, all-out program”). Clean and disinfect between each group of broilers.

 Buy chicks from good hatcheries that are guaranteed to have no mycoplasma. Chicks from these hatcheries may cost more.

 Blood test hens. Use eggs for hatching only from those hens that test negative.