In May 2003, West Central Research and Outreach Center (WCROC),
University of Minnesota, completed a new housing system for sows and piglets.
Formerly a dark, smelly structure for housing pigs over a liquid manure pit, the
newly remodeled building underwent a remarkable transformation. Modeled on a
Swedish system, it houses pigs in amply lit rooms, amidst an abundance of straw,
with plenty of room to roam, socialize, root, and give birth to their young.
AWI’s Farm Animal Economic Advisor Marlene Halverson contributed to the design.
The 45 foot by 120 foot building is divided into four
spacious rooms. Each of three rooms houses eight sows and their piglets, while
one room houses gilts (young female pigs) “recruited” from the WCROC pig herd to
become breeding sows. At one end of each room, “garage” type doors permit easy
cleaning and rebedding with a small tractor.
Individual feeding stalls and a deep straw bed in the
gilts’ room mimic the layout of the Center’s gestation hoop (see Winter 2004 AWI
Quarterly). Gilts gain experience living in groups and using feeding stalls
before joining the main sow herd. Fresh straw added daily provides material for
occupation and is consumed by the gilts between meals.
In the farrowing (birthing) rooms, staff set up eight
portable farrowing pens, four along each sidewall, with pen entrances facing a
spacious area in the middle. They bed each pen with straw. Sows are brought into
the rooms a few days before they are due. Soon after, each sow chooses a pen in
which she arranges a nest and gives birth. The seven foot by ten foot pens are
roomy enough that sows can enter, lie down to nurse, rise, and leave again with
a low incidence of injuring piglets. When all piglets can climb out of the pens,
the pens are dismantled and removed so piglets and sows can mingle freely.
Sows naturally begin to wean piglets by reducing the
number of nursings they initiate. Because feed is continuously available in the
farrowing rooms, piglets learn to eat by their mothers’ sides. Their digestive
systems become accustomed to solid feed. Staff complete the weaning process when
piglets are five to six weeks old by taking sows to the gestation hoop for
rebreeding. Sows’ scents are left behind in the beds, reducing piglets’ stress
associated with their “loss.” A five to six week nursing period allows young
pigs’ immune systems to develop. Reducing the stress of weaning helped Swedish
pig farmers adjust to Sweden’s legal prohibition on subtherapeutic antibiotic
use. By contrast, industrial production entails weaning piglets abruptly at one
to three weeks of age.
 |
|
Removing the birthing pens
simulates the process in nature, when sows leave their isolated farrowing nests
and lead piglets to join the larger, communal group.
|
WCROC is pleased with the system. Sows farrowing in
October 2003 weaned an average of 10.5 pigs per sow. Because the Center
remodeled an existing building rather than building new to Swedish
specifications, getting the ventilation system to work properly has been a
challenge as has learning to manage deep straw beds, but workers are adjusting.
If successful, the remodeling can provide an example for farmers who have
buildings they would like to convert. The systems elicited favorable responses
from farmers attending a November 2003 “open house.” AWI applauds this
progressive research to improve pig welfare.
