How can farmers identify and control Mycoplasma gallisepticum (MG) infections in brown egg flocks to prevent chronic respiratory disease and egg production drops?

Mycoplasma gallisepticum (MG) is a slow-spreading, chronic respiratory pathogen that causes major economic losses in multi-age brown layer operations. The disease manifests as Chronic Respiratory Disease (CRD), with clinical symptoms including tracheal rales, coughing, sneezing, nasal discharge, and infraorbital sinusitis. In laying hens, it causes a slow, persistent decline in egg production (up to 15%) and poor eggshell quality. Diagnosis is confirmed via serum plate agglutination (SPA) or PCR tests. To control MG, infected flocks are treated therapeutically with macrolide antibiotics such as tylosin, tilmicosin, or tiamulin in drinking water. However, antibiotic treatment does not eliminate the carrier state; hence, long-term control on multi-age sites relies on immunizing replacement pullets with live MG vaccines (like the F-strain or ts-11 strain) at 10 weeks of age. Respiratory health is detailed in the Poultry Encyclopedia, diagnostic kits and veterinary therapeutics are sold on Poultry Plaza, live bird mandi rates are updated on Poultry Rates, and commercial egg operations are listed on Murghi Mandi.