Research shows that pigs going to market in the hot summer months are more likely to die in-transit than pigs shipped during cooler times of the year.
When pigs are heat-stressed and their body temperatures rise, they are at risk of collapsing and may die due to cardiovascular failure. Not only is this an animal welfare concern, but heat stress can also affect meat quality.
This led Ontario Pork to undertake an innovative project to try to keep pigs from overheating while they were waiting to be unloaded from trucks at processing plants.
“When a truck is moving down the road, heat isn’t as much of an issue as it is when the truck is stationary, like it is when it is waiting to unload pigs at a processing plant,” explains Sam Bradshaw of Ontario Pork.
As part of the project, a bank or wall of fans was set up at two Ontario processing facilities so that trucks waiting to unload their livestock could pull up next to them and let the air blow through, cooling the animals inside.Each fan bank was equipped with eight 48-inch basket fans delivering 28,000 cubic feet per minute (cfm) each for a total of 224,000 cfm, and four 36-inch fans delivering 12,000 cfm each for a total of 48,000 cfm. This delivered a total air flow of 272,000 cfm, and resulted in airspeed of 300 feet per minute flowing through the entire trailer, the level recommended to cool pigs sufficiently.Data loggers monitoring temperature and relative humidity were installed in livestock trailers delivering hogs to both processing plants.
According to Bradshaw, study results showed that on a day with an outside temperature of 32.5C, the temperature inside a parked truck quickly climbed to 36.8C within an hour, but when the fans were turned on, that temperature dropped to 34.5C in only 15 minutes.
A weather safety index for pigs states that a temperature of 32C with relative humidity of 33 per cent is a “danger” zone for pigs, and that status rises to “emergency” when the relative humidity increases to 68 per cent, says Bradshaw.
“The fans took us from the emergency zone down into the danger zone simply by blowing air through the trailer,” he says. “After the trailer arrived at the plant and was parked for a while on a hot day, the pigs would be lying down and panting, but as soon as they got in front of the fans, they’d start looking around, standing up and just being more comfortable.
”Although one of the processing facilities in study is no longer in business, the fan bank is still in use at the other plant and is in fact scheduled to be expanded to accommodate more trucks.“I think this is something that we really need at all processing plants. We talked to a lot of transporters during this project and they all said this is just great for the pigs,” Bradshaw says.
“In fact, some transporters are now experimenting with on-board ventilation systems that run off a truck’s electrical system and keep temperatures cool during the entire transportation process,” he adds.
Source: AlbertaPork