RED DEER — Sows moved into open-housing systems can sometimes start fighting for food and territory.
In the wild, they live as family groups called sounders where there is less aggression because they know each other.
In domestic barns, the group is more unstable. They live in a limited space with strangers and they are constrained, which can lead to frustration and aggression as they struggle to sort out a pecking order.
“We expect them to live in fairly challenging conditions and I think they do very well and produce well considering this,” said animal welfare specialist Yolande Seddon of the University of Saskatchewan.
One of the leading causes of aggression is hunger, she said at the 2019 swine technology workshop in Red Deer.
“We know when we have a deficiency in our nutrition programs this also causes aggressive behaviour because there is frustration building in individual animals. They are unable to meet a need they are detecting,” she said.
Sows can learn social skills but aggression can break out when unacquainted animals meet in a confined space and try to form a hierarchy. After that hierarchy is developed the physical aggression should end.
Sows may get battered and may be covered with lesions. Head-to-head fighting with bites or body knocks can be damaging. A sow could lose weight or a pregnancy under increased aggression.
That would suggest some are very physical and do not back down from a fight. Producers need to review the aggression if lesions persist during the gestation period.
“Sows should not die from aggression. They should be able to respond and move on,” Seddon said.
Other injuries may occur if the flooring is not adequate. Lameness and claw injury can occur if toes get caught in slatted floors during a fight.
The first three days after grouping is the critical time when injuries may occur. Strategies to reduce aggression at the initial mixing time may actually prolong aggression by delaying dominance formation.
There are a variety of strategies for sows in group housing.
Adequate space gives pigs a chance to avoid each other. They need a place to lie down so walls could be placed strategically for them to sleep against or hide.
“If the sow on the receiving end is not able to get away that will escalate the situation right away,” she said.
Some recent inventions may also help.
Jostling around the feed or water can cause commotion and injuries. Electronic sow feeders provide an individual meal for sows and protects them as they eat.
One company played a tune for an individual and each sow learned this was her feeding time. Calling the sow for a meal reduced aggression at the feeder.
The company holding the patent for the tunes is now looking at an ear tag vibration rather than playing music. The biggest challenge is finding a battery that lasts throughout the gestation period.
Helping pigs develop social skills at an earlier age could also help. If 10-day-old piglets meet new pigs they learn to socialize better.
“We have a lot of research that indicates that we will actually have shorter fight bouts that are more intense, and contests ended more quickly with fewer injuries when we were able to pre socialize animals at an early age,” Seddon said.