Weather fluctuations, particularly during seasonal transitions, create significant stress in poultry production systems. Sudden changes in temperature, humidity, ventilation patterns, and air quality weaken the birds’ immune defenses and predispose them to respiratory infections. Among these, Mycoplasmosis is one of the most economically important diseases affecting both commercial layers and breeder flocks.

The two major pathogenic species affecting poultry are:
– Mycoplasma gallisepticum infection (MG)
– Mycoplasma synoviae infection (MS)
These organisms are highly contagious and often become more problematic during changing weather conditions due to increased environmental stress and compromised flock immunity.

Why Changing Weather Increases Mycoplasma Problems
During weather transitions such as:
– Summer to monsoon
– Monsoon to winter
– Sudden cold or heat waves
birds experience physiological stress that suppresses their immune response. Several environmental factors contribute to Mycoplasma outbreaks:
1. Temperature Fluctuation
Rapid day-night temperature variation stresses birds and damages the respiratory mucosa, making it easier for Mycoplasma organisms to colonize the respiratory tract.
2. Poor Ventilation
Farmers often reduce ventilation during cold weather to conserve heat. This increases:
– Ammonia levels
– Dust accumulation
– Humidity
– Carbon dioxide concentration
Such conditions irritate the respiratory tract and favor Mycoplasma multiplication.
3. High Humidity and Wet Litter
During monsoon seasons, excessive moisture increases pathogen survival and worsens respiratory stress.
4. Secondary Infections
Changing weather also favors bacterial and viral co-infections such as:
– Newcastle disease
– Infectious bronchitis
– Escherichia coli infection

These infections intensify the severity of Mycoplasma disease.
Clinical Signs in Layers and Breeders
Affected birds may show:
– Coughing and sneezing
– Nasal discharge
– Rales and respiratory sounds
– Swollen sinuses
– Watery eyes
– Reduced feed intake
– Depression and poor growth
– Increased mortality in severe cases

In breeder flocks, fertility and hatchability may decline significantly.

Impact on Layer Performance
Mycoplasma infection severely affects commercial egg production.
1. Drop in Egg Production
Layers infected with MG or MS commonly show:
-Sudden reduction in egg production
– Irregular laying patterns
– Delayed peak production
Production losses may range from 5–20% depending on flock condition and secondary infections.
2. Poor Egg Quality
Infected layers may produce:
– Thin-shelled eggs
– Misshapen eggs
– Smaller eggs
– Poor shell strength
This increases breakage and market rejection.
3. Increased Feed Conversion Ratio (FCR)
Respiratory stress reduces feed efficiency, increasing production cost per egg.
4. Increased Culling and Mortality
Chronically affected birds become poor performers and require early culling.

Impact on Breeder Performance
The economic effect of Mycoplasma is even more serious in breeder operations.
1. Reduced Fertility
Mycoplasma infection negatively affects reproductive performance, lowering fertility percentage.
2. Poor Hatchability
Vertical transmission through eggs can infect embryos, causing:
– Embryonic mortality
– Weak chicks
– Poor hatchability
3. Transmission to Progeny
MG and MS can spread from infected breeders to chicks through eggs, creating long-term farm problems.
4. Reduced Chick Quality
Chicks from infected breeder flocks often show:
– Weakness
– Respiratory distress
– Poor growth potential
– Higher early mortality

Economic Losses
Mycoplasma outbreaks during changing weather can lead to major financial losses through:
– Reduced egg production
– Poor hatchability
– Increased medication costs
– Mortality and culling
– Lower chick quality
– Increased feed costs
– Trade restrictions in breeder operations

Diagnosis
Accurate diagnosis is essential for effective control. Common diagnostic methods include:
– Serological testing (ELISA, SPA)
– PCR testing
– Culture and isolation
– Postmortem examination

Typical lesions include:
– Air sacculitis
– Tracheitis
– Foamy air sacs
– Pneumonia

Prevention and Control Measures
1. Maintain Proper Ventilation
Ensure adequate airflow without creating drafts.
2. Reduce Environmental Stress
– Maintain uniform temperature
– Avoid sudden temperature changes
w Control humidity levels
3. Strengthen Biosecurity
– Restrict visitor movement
– Disinfect equipment
– Control wild birds and rodents
4. Vaccination
Vaccination programs against MG and MS should be followed according to veterinary recommendations.
5. Early Medication
Prompt treatment using appropriate antimicrobials under veterinary guidance can reduce severity.
6. Improve Litter and Air Quality
Regular litter management helps reduce ammonia and dust.
7. Nutritional Support
Provide vitamins, electrolytes, and immune boosters during stressful weather periods.

Conclusion
Changing weather conditions significantly increase the risk and severity of Mycoplasma infections in poultry farms. Layers suffer from reduced egg production and poor egg quality, while breeders face severe reproductive and hatchability losses. Because Mycoplasma infections often become chronic and difficult to eliminate, prevention through good management, ventilation, biosecurity, and stress reduction remains the most effective strategy.

Early detection and timely intervention are essential to maintain flock health, productivity, and profitability during seasonal