There is no doubt that most pig producers around Australia have suffered a long hot summer, and many wish they had better ventilation and cooling for their pig housing. With climate extremes becoming more the norm, it is time to start thinking about how our pigs will fare next summer.
Proper ventilation design is essential for any form of pig housing. It is worth noting that ventilation airflow capacity does not necessarily mean ventilation quality, so just putting extra fans in a convenient spot doesn’t always solve the problem. We also need to consider that ammonia is lighter than air, but carbon dioxide and air-borne dust is generally heavier than air, so avoiding air stratification is essential. Successful ventilation systems provide well‐directed and uniformly distributed airflow without excessive draughts or dead spots. This will serve the needs of livestock much better than uncontrolled, high ventilation throughput.
High temperatures reduce feed intake, but low temperatures reduce food to body mass conversion, so having good temperature control in pig housing can significantly benefit productivity. Well designed climate controlled buildings provide optimal growing conditions year round and minimise heat stress losses during summer.
Evaporative cooling is an ideal solution for livestock housing because it can deliver large volumes of cool air at a reasonable energy cost. However with pigs, drawing air in one end of a building and discharging it at the other is less than ideal. The pigs at the upstream end will probably be overly chilled and subject to high air draught, while the pigs at the other end may be breathing stale and contaminated air. A better solution is to uniformly distribute cooled air throughout the building using engineered air inlets that provide uniform air flow and de-stratification of the air space. The air is then drawn out across the shortest path, giving better air quality for the last pig in the airflow pattern.
Studies have shown that ammonia contaminated air in pig housing reduces feed intake and increases risk of lung diseases. There are some discrepancies on exactly what is a safe ammonia concentration, however the CSIRO Model Code of Practice for the Welfare of Animals – Pigs, recommends a maximum ammonia pollutant level of 11ppm. Given that the human threshold of detection for ammonia odour varies from 0.5ppm to 50ppm, in many cases if you can smell ammonia in the air, the ventilation is inadequate.
Of course, looking after our workers is also a primary concern. Safe Work Australia’s Workplace Exposure Standards for Airborne Contaminants limit the Time Weighted Average (TWA) for exposure to Ammonia to 25ppm and the Short Term Exposure Limit to 35ppm.
Mundigo have over 20 years of experience with designing ventilation and cooling systems for pig housing. Starting from scratch where quality ventilation and cooling are integrated into the building design is obviously best, but there are many things that can be done to improve existing buildings. At Mundigo, we like to combine some HVAC science, with our sound knowledge of Australian conditions to produce ventilation and cooling designs that work for the producer. Mundigo source components from around the world, from multiple specialist manufacturers to deliver the best total system solutions.