Feature
Scientist Yuzhi Li is experimenting with housing systems for sows and piglets at the West Central Research and Outreach Center in Morris.
A life of leisure
U researchers studying better housing for livestock animals
By Becky Beyers
From eNews, July 24, 2008
It seems logical: A contented livestock animal is a productive
one. And of course farmers want the best for their animals. But
animal comfort issues have to be balanced against the need to make
a living. Productivity and economics usually take precedence over
providing all the comforts of home in the barn. That choice is
becoming less black-and-white in some livestock barns, as consumers
seek food products from animals raised under more humane
conditions, and as research by scientists at the University of
Minnesota's College of Food, Agricultural, and Natural Resource
Sciences helps find new ways to keep animals happier without
breaking the bank. The following are two examples of what the U is
doing for pigs and cows.
Eliminating stalls for swine
Pigs are animals that naturally socialize with each other, says
Yuzhi Li, an assistant professor of animal science who works on
alternative swine systems at the U's West Central Research and
Outreach Center (WCROC) in Morris. But most sows are housed in
tight-fitting stalls during pregnancy and farrowing that restrict
their movements. The stalls became the industry standard in the
mid-1970s because of their efficiency, but researchers have found
some sows' behavior and health decline while confined. Li has been
testing sow group housing, where sows and piglets move around
freely in a pen with thick straw bedding that absorbs most of their
manure. The setting allows each sow to choose its micro-environment
and companions, resulting in more natural behavior with less risk
of lameness and difficult pregnancy and birthing. Gestation stalls
have been outlawed in Europe; in the United States, movement away
from them has been driven by consumers, rather than legislation.
Last year, the nation's biggest pork supplier, Smithfield Foods,
says it was responding to demands from its customers--including
McDonald's--by requiring its growers to phase out gestation stalls
in the next 10 years. Those changes eventually will filter down to
Minnesota pork producers, Li says. While fewer than 5 percent of
producers now use group housing of both gestating and farrowing
sows, she expects that number will grow as scientists find ways to
solve the challenges of group housing--primarily sows that crush
their piglets by lying down on them and aggression and biting
between sows. Gathering more data will help find solutions to those
problems, Li says. For example, two studies at the WCROC may help
reduce the sows' aggressive behavior and reduce piglet mortality.
One involves adding tryptophan--the same amino acid that is
believed to make humans sleepy after Thanksgiving dinner--to the
pigs' diets to reduce their aggression. Another behavioral study
shows that first-time mothers who crush their piglets tend to do so
with subsequent litters; it's possible that eliminating those
careless mothers from the herd will eventually help reduce piglet
mortality, Li says.
Flies: A never-ending problem
Roger Moon has spent years dealing with a different animal comfort
issue, one that has no easy solution: flies. "For horses, it's
mainly a question of comfort, but with food animals it could affect
their productivity," says the professor in the U's Department of
Entomology. Until about the 1940s, flies were simply a fact of
life; since the advent of insecticides, animals can get some
relief, but the insects have evolved resistance in some cases, and
eliminating all flies just doesn't seem possible. Four main kinds
of flies affect livestock in Minnesota: the stable fly, the horned
fly, the house fly and the face fly. Stable flies in particular can
affect dairy production, because in summer heat, the cows bunch
together and don't eat as much while trying to get away from the
flies. Face flies have a more visible effect--they can cause
pinkeye in cattle because they feed on tears and mucus around the
cows' eyes and nose--but no one has traced that discomfort to a
direct effect on productivity, Moon says. "It's difficult to deal
with pests in animals," he says. "For plants, dealing with pests
comes to simple economics. But with animals, there's this other
dimension." While Moon has researched the question of biological
control--finding a natural enemy that could be introduced in
Minnesota barns to eliminate flies--the search found few
possibilities, he says. "Our basic sermon to farmers at this point
is to understand where the flies come from and try to eliminate
these sources through prevention, sanitation, and waste disposal,
including composting. Source reduction is really about the only
thing that works." To learn about the U's research with housing for
cows, read
Got more milk?" and "Maternity
spa for cows" .