In an effort to establish welfare-friendly guidelines on how to effectively manage gestating sows, researchers at the University of Illinois are studying the impact of stall design on sow behavior and well-being.
"Sows have changed," says Janeen Salak-Johnson, U of I associate professor of animal science. "We need to change with them. Our research shows modifying the stall design may have a positive effect on sow behavior and well-being."
In this study, sows were evaluated in a standard gestation stall and a turn-around gestation stall. A turn-around gestation stall pairs two sows together with a shared divider that allows one sow to turn around at a time without difficulty. Researchers compared the behavioral differences of housing sows in standard or turn-around stalls for 30 days prior to placing some sows in group pens and leaving some sows in stalls for the remaining gestation period.
Slight modifications to stall design can impact sow behavior
Preliminary findings show that slight modifications to stall design impact measures of well-being, particularly behavior and immune status. "Sometimes behavior is the best adjustment an animal can make in a stressful situation," Salak-Johnson says. "Making modifications to the gestation stall may allow sows to adapt more easily to stressful situations without experiencing negative consequences."
From a behavior standpoint, researchers observed that stall design modifications also resulted in differences between sow groups. Sows in standard stalls sat more, while sows in turn-around stalls lay more. Oral-nasal-facial activity (ONF) increased in sows in turn-around stalls as they approached gestation. However, sows in standard stalls engaged in less ONF overall and remained consistent in the amount of ONF they displayed throughout the gestational period.
In previous studies, immune status has been affected more by day of gestation rather than actual treatment. However, U of I's research indicates the stall design may impact sow immune status. Sows in turn-around stalls had greater lymphocyte activity which indicated a more stimulated immune response compared to sows in a standard stall.
Data shows an immune response to different types of sow stalls
"This is one of the first sets of data that has shown an immune response to stall types," Salak-Johnson says. "The next step is to figure out what these differences mean and which response is better for the sow."
An activated immune system could imply either a sow's biological defense to stress or a sow's readiness to fight off infection if challenged with a pathogen. Salak-Johnson and her team are interested in discovering the positive physical components of each stall type and combining the positives together in order to make housing recommendations. "If you really want to find the best option, you need to see research results that prove one housing option is better than the other," she says. "Right now, that information doesn't exist. People want to throw sows in group pens to avoid certain behaviors such as ONF. However, ONF may actually be better for the sow."
Researchers are also detecting differences between sows housed in standard stalls before moving to group housing and sows housed in turn-around stalls before moving to group housing. While there are no differences in ONF, researchers have observed differences in two maintenance behaviors – lying down and standing.
The latest in-depth findings will be presented at the 2010 American Society of Animal Science Annual Meeting in July. This research was funded by the National Pork Board. Researchers include Ashley DeDecker and Janeen Salak-Johnson of the U of I, and Paul Walker and Andrea Hanson of Illinois State University.