Calm, cool and collected | Pigs with passive traits get less stressed, improving meat quality
Breeding pigs for passive, calm traits can increase producers’ bottom lines and reduce the stress of handling for both pig and human.
Jennifer Brown of the Prairie Swine Centre near Saskatoon has studied pig temperament to find methods of determining traits so that producers can develop less stress-prone herds, lower mortality and increase meat quality.
Brown’s research team created four tests to determine which pigs display the most ideal traits.
Two of the tests measured active and passive traits:
- The open door test measured the time it took pigs to explore a door into a new area.
“You’re opening a door and they’re not sure where it goes to,” Brown said. “The animals that are more active are more inclined to leave the pen sooner. The ones that are passive are just going to hang back.”
- The novel object test isolated pigs in a small pen with three unfamiliar objects. It measured how long it took the pig to approach and contact the object, how many times it interacted with them and how frequently it moved from one object to another.
“An active animal is going to be quicker to approach something unfamiliar and make contact, but it’ll move on quickly and explore multiple objects,” Brown said. “Whereas with a more passive temperament, they’re going to be slower to approach, (and when) they actually do contact something unfamiliar, they’ll spend more time exploring that object.”
The other two tests measured confidence and fear in relation to humans, testing a pig’s willingness to approach a human or remain still when a human approaches.
“A confident animal is more likely to stand and then sniff your boots sort of thing when you get close to them,” Brown said.
Active animals use lots of energy if they’re being transported over long periods. Passive animals conserve energy but will experience acute stress at the processing plant because they’re not willing to move, Brown said. Excess energy use results in red, soft pork.
“They’ve used up their energy. Then they also experience stress when they’re going through slaughter. It’s a combination of meat quality problems. It’s all related to what’s left in the muscle after being held off feed and transported.”
However, passive animals can also produce pale, soft pork if subjected to acute stress before slaughter.
Brown said animals that are managed in confinement are in competitive situations. Aggressive animals are inadvertently selected because they are doing the best competitively. This aggression can lead to problems such as tail biting. With chickens, it takes the form of cannibalism.
“We need to recognize when that’s a problem and try to select for animals with a more passive temperament that are going to be less aggressive in a social situation,” she said.
However, some aggression supports maternal instincts, such as when a sow protects its piglets.
Brown said breeding for passive traits in combination with calm traits is the best approach when selecting pigs for temperament. Management that allows pigs to become accustomed to handling can reduce stress when they are shipped.