Farmers are used to the bench-clearing brawls that occur when pigs are
mixed in a pen for the first time.
Each pig wants to fight every other pig until they have sorted
themselves into a hierarchy from the meanest goon to the weakest wimp.
That’s why most producers have avoided using large group pens. If 10
pigs in a pen can cause a brawl, 200 in a pen might start a
pigpocalypse that would badly hurt productivity and leave a lot of
Read Also
USDA’s August corn yield estimates are bearish
The yield estimates for wheat and soybeans were neutral to bullish, but these were largely a sideshow when compared with corn.
injured animals.
But Harold Gonyou of the Prairie Swine Centre had good news for
Manitoba producers at the centre’s recent conference in Winnipeg: pigs
in big pens don’t fight for any longer than pigs in small pens. They
all run out of scrappiness in the same amount of time.
That means large group housing of grower-finisher pigs is a viable
option for commercial hog producers.
“This is definitely something we can look at,” Gonyou said.
“They don’t have to keep fighting until they’ve fought every pig in the
pen.”
The swine centre is comparing grower-finisher pigs raised in 10-pig
pens and 80-pig pens to examine their aggressive behaviour and how that
affects productivity.
It is also studying a farm that uses pens that contain more than 200
pigs each.
Group housing may be a way for producers to save money. Barns that
contain a few large pens may be cheaper to build than those with many
small pens.
As well, pen design would be more flexible and labour costs would be
less, Gonyou said.
Until recently, producers didn’t think much about large pens because
they wouldn’t have made sense for smaller farms. When the industry was
dominated by 60-sow barns, only 30 pigs per week reached
grower-finisher status.
Now, in a 600-sow operation, which is at the smaller end of the modern
hog industry, 300 pigs per week are graduating to grower-finisher.
But most producers with larger barns haven’t adopted large pens. Gonyou
said that’s because most producers assume pigs’ natural aggressiveness
in new environments would lead each pig to a series of fights that
would leave most exhausted, and many badly beaten up.
But Gonyou said his studies have shown that pigs always tend to fight
when they’re put into a new social setting, but they always give up
after about two hours.
They don’t feel compelled to fight every other pig, and they don’t form
tribes. Gonyou said that after the initial fighting is over, the pigs
circulate in the pen amicably, rather than dividing up the area.
There also haven’t been problems with extreme victimization of a few
subordinate pigs, nor a super-aggressive pig causing all the other pigs
to go into a biting frenzy.
Gonyou found that pigs in big pens become less aggressive if introduced
into another big pen compared to small-pen pigs that are moved into big
pens.
The pig from the small pen tends to aggressively confront other pigs in
the new pen, but the pig from the larger pen tends to be only half as
aggressive, Gonyou said.
He compared the situation to the difference between human beings in a
small town and a city. People in a small town tend to be closely
involved with each other and changes cause big reverberations, while
people in a city notice each other less and are used to living with a
much more diverse population.
Gonyou said past research has tended to reinforce the idea that big
pens create big fights, but those studies aren’t generally relevant to
today’s farming practices.
They compared pigs in 10-pig pens to those in 30- or 40-pig pens.
Gonyou said 80-pig pens create an entirely new social environment.
Gonyou said there is much to learn about pig behaviour in a big pen.
They sleep and dung differently, for instance, which has to be taken
into account when designing a barn.
But the research also shows that practices people thought wouldn’t work
with pigs are possible and viable.
“I was surprised,” admitted Gonyou, who had expected to find more
fighting in the big pens.
