4 steps to tackle porcine respiratory disease complex
© Tim Scrivener As winter sets in, so the risk of respiratory disease goes up.
I have seen an increase in cases on several pig farms recently, especially following cold, dank days and large variations in temperature from day to night.
Porcine respiratory disease complex (PRDC), as the name suggests, is multifactorial in cause. It can be a persistent and challenging issue, especially during the colder months.
About the author
Julia James is a senior partner at Larkmead Vets. She specialises in large animals and heads up the farm animal team.
Viruses and bacterial pathogens, as well as non-infectious factors such as ventilation, housing and the weather, all play a part.
It can have a significant impact on the health, welfare and productivity of a unit, so it needs to be addressed promptly.
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Damaged immune system
The onset of cooler temperatures, shorter daylight hours and increased humidity during autumn and winter create an environment that is conducive to the growth and spread of respiratory pathogens, especially common viral infections such as porcine reproductive and respiratory syndrome and influenza A.
These viruses can significantly damage the pig’s immune system, providing an opening for secondary bacterial infections such as Pasteurella multocida or Actinobacillus pleuropneumonia.
Cold weather often leads to reduced ventilation in buildings, increasing the likelihood of disease spread.
The stress of temperature changes also weakens the immune system, making pigs more susceptible to infections.
The interplay of all these factors can make PRDC very difficult to manage.
Signs and symptoms
Early detection and intervention are critical in preventing PRDC from escalating.
It can present in various ways, but common symptoms include coughing, nasal discharge, rapid or laboured breathing, lethargy, and reduced feed intake. In acute or untreated cases, this can progress to death.
Strategies to combat PRDC
Preventing and controlling this disease during the autumn and winter months requires a multifaceted approach, focusing on environmental management, biosecurity, vaccination, and nutritional support:
1. Good ventilation is key, but avoid chilling
It may be tempting to reduce airflow to conserve heat, but this can lead to a build-up of harmful pathogens and excess moisture.
Instead, ventilation systems should be designed to bring in fresh air without creating draughts, while also allowing for the removal of ammonia and humidity.
Producers should check and maintain ventilation systems regularly to ensure optimal air quality.
2. Implement effective biosecurity measures
Given that respiratory diseases are highly contagious, biosecurity is critical in preventing the spread of infection.
This includes ensuring that incoming pigs are from a known, healthy source, restricting visitor access to the farm, and thoroughly disinfecting vehicles and clothing.
3. Follow farm-specific vaccination protocols
Vaccinating against common viral and bacterial pathogens that contribute to PRDC is essential for reducing the risk of outbreaks, and to help lower the severity of known infections on-site.
Producers should consult with their vet to tailor vaccination schedules to the specific needs of their herd.
4. Manage nutrition for strong immunity
Ensuring pigs have access to high-quality nutrition is vital for maintaining a robust immune system.
During cold weather, pigs may require higher energy intake to maintain body heat.
In addition, a balanced diet with sufficient vitamins and minerals, particularly vitamin E and selenium, is essential for immune function.