Animal stress affects meat quality

Quality pork depends on a lot of factors, among them is how pigs are transported to the slaughterhouse.

Yolande Seddon and other researchers at the Prairie Swine Centre have been investigating the causes of swine stress during transportation and notes the Prairies have some particular transportation challenges to overcome.

“We know there are very challenging conditions within Canada, so even if (pigs) happen to arrive dead, we know that there are a lot of issues in relation to the transport times and the amount of stress caused,” she told producers during a swine seminar in Niverville.

Those conditions include extreme heat and cold, as well as lengthy journeys.

By monitoring animal behaviour during travel, Seddon and colleagues were able to identify behaviours showing temperature stress.

In cold weather pigs avoid touching trailer flooring, while in hot weather, animals would lay down on the metal to cool off. While bedding material is provided, the researcher noted it can shift to one side of the trailer during loading, leaving some animals exposed.

Which trailer compartment a pig is located in also has an effect on temperature, air pressure and stress, with some areas maintaining a more pleasing ambient temperature than others.

The ramps pigs enter and exit a trailer on can also cause stress, especially if electric prods are used, Seddon said.

“That really winds the pigs up, creating a bad situation,” she explained.

And that stress can negatively impact meat quality.

Acute stress and adrenaline produce pale, soft, exudative meat with a high drip loss, while longer-term stress depletes glycogen in muscles and produces meat that is dry, firm and dark.

But the impetus for the transportation study came from the number of pigs dead on arrival.

“We look at a point one per cent loss and say, oh well that’s not that much,” said Lee Whittington, Prairie Swine Centre CEO. “But when you look at how many pigs are handled across the country, all of a sudden you’re talking about 16,000… so you have to ask, how many truckloads are simply wasted?”

But there are ways to reduce stress for animals during transportation.

“What the producer can do is really only what is on his farm, and that is making sure your pigs are less flighty by talking, walking the pens and handling them as calmly as possible,” Seddon said.

In hot weather it’s also advisable to sprinkle pigs with water and get the truck moving as quickly as possible to start airflow through the trailer.

“But as soon as the pigs leave the farm it’s up to the truckers,” said Seddon. “Sometimes as the farmer is loading pigs calmly, the stockman is prodding, undoing all the positive.”

That issue may be driven in part by trailer designs that require many ramps.

“We know from Europe that there are different methods of loading, including hydraulic lifts that eliminate the need for ramps altogether,” she said.

But using hydraulic lifts would require expensive changes to trailers, and off-loading facilities.

“It’s not a quick-fix solution, so I think for now we need to be looking at existing trucks and see how we can alter boarding patterns, how the airflow is entering the truck, and how as handlers we can get the pigs on as calmly as possible,” Seddon said.

About the author


Shannon VanRaes is a journalist and photojournalist at the Manitoba Co-operator. She also writes a weekly urban affairs column for Metro Winnipeg, and has previously reported for the Winnipeg Sun, Outwords Magazine and the Portage Daily Graphic.



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