CRD is a specific disease caused by one of the group of organisms known as pleuro pneumonia like organism (PPLO), but more closely defined is Mycoplasma; the particular organism directly associated with CRD is Mycoplasma gallisepticum with or without secondary complications.
The mortality entirely to CRD is negligible, but it is important because it predisposes the birds to infection for other disease producing organisms.
M. gallisepticum is transmitted through eggs but organisms can also pass from bird to bird through nasal discharges and through droppings. It can also be transmitted by hands, feet and clothes of attendants of visitors. Symptoms: Uncomplicated CRD is frequently sub-clinical. When symptoms are present they normally include coughing, sneezing, and a nasal discharge. In turkeys, sinuses are frequently swollen. On postmortem examination the trachea may be found inflamed and the air sacs thickened with pus. The condition affecting air sac is often referred as “air sac” disease but it is more pronounced when other factors including bacteria, complicate the original CRD infection.
The organism has long incubation period of 10 to 30 days. Therefore only few outbreaks-seen in birds under 4 weeks old.
Prevention and control:
As uncomplicated CRD is not a major problem today, it may be necessary to protect only against the probable complicating factors. Increased ventilation without drafts reduces the spread and severity of CRD. Buying replacement stock from CRD free source greatly reduces the risk of spread. A very high standard of hygienic condition is of course, supremely important.
To enhance immunity and prevent CRD for poultry, should mix APA Antistress P (which contains Vitamin C 50%, Acid citric 50%) with feed or dissolve in drinking water for poultry to drink all day long. After 2-3 weeks, farmers should supply poultry with essential vitamins and minerals. APA Soluvita P is a very good source of necessary vitamins, amino acid, to improve growth of poultry, stabilize FCR and health for poultry.
The tetracycline group of drugs is useful in treatment, if given continuously for over a week, as soon as disease’s seen in flock. It can also be given through water.
For treatment of CRD, APA’s now providing a very wide range of powder products including APA Flo Do P (Florfenicol 10%, Doxycycline 5%), APA Linco Spec P (Lincomycin HCl 5%, Spectinomycin HCl 10%), APA Tylodo P (Tylosin Tartrate 5%, Doxycycline hyclate 5%), which can be mixed in feed or completely dissolved in drinking water.
Source: agriviet com, agriinfo in