“Heat is a major problem for pigs because pigs do not sweat.”
Pigs react strongly to the temperature on trucks and to handling methods, said the researchers of a multi-provincial hog transport study. Luigi Faucitano, a research scientist with Agriculture Canada in Sherbrooke, Quebec, delivered a report on the study’s findings of the Swine Handling and Transport trials to a recent seminar here.
The trials in Eastern Canada found that the outdoor temperatures averaged about 20 to 21C summer and about 8 to 9C in winter. As expected, when the vehicle is waiting or idling, the temperature inside the truck increases, said Faucitano.
The temperature was found to vary in each compartment of the truck, causing variations in core body temperatures of pigs. Hogs that had to climb ramps or wait in the upper deck of a truck also showed an increase in core body temperature. “Heat is a major problem for pigs because pigs do not sweat,” said Faucitano. “Pigs get rid of excess heat through panting, especially under hot and humid conditions.”
Faucitano said the mortality rate of pigs increases with temperature and doubles when temperature exceeds 22.5C. The research team thinks pigs could benefit from fans which would provide ventilation in the trucks. Misting pigs with cool water through a hose or sprinkler may also help cool them.
Colder temperatures in winter caused some truck compartments to drop below freezing. Insulation inside the truck may alleviate this, Faucitano said.
Truck design also affects pig welfare, but should be combined with better handling tools. Faucitano said research shows that prodding pigs with electrical prods contributes to increased stress for the animals. Pigs handled with the prod slipped more, overlapped more and slowed down the entire loading and unloading process. Pigs handled with the electrical prod always showed a much higher heart rate and increased bruising on their carcasses.
Faucitano said researchers are experimenting with encouraging the pigs to move by use of a compressor prod, but more research on its benefits is needed.