Swine welfare closely studied at Penn Vet


Sally Silverman

Pigs at New Bolton Center's Swine Research and Training Center.

Human beings have been influencing the evolution of the pig for more than 10,000 years. Descended from the hairy, ornery wild boar, modern pigs’ physical forms and everyday lives are increasingly molded by human technology.

But at New Bolton Center’s Swine Teaching and Research Center, progress in pig-farming means figuring out how best to return to older practices while still moving forward.  

For the last four decades, mother sows—who birth and rear the piglets that grow up to be slaughtered for food—have been mostly raised in gestational crates. These narrow enclosures give farmers a high level of control over the nutrition and health of their pigs. By the same token, these crates limit the sow’s movement and prevent her from turning around, so animal welfare concerns have led to the technique being phased out in Europe and in several American states.

At the Swine Research and Training Center, sows once again live in pens, not in crates. But a more natural lifestyle for pigs is not without its own welfare challenges. Left to their own devices, sows develop strong social hierarchies. Dominant sows sometimes harass and injure those under them on the status ladder. But the most pressing problem involves food. Dominant sows consume communal food at the expense of the lower-status animals, resulting in both obese and malnourished sows, neither of which is good for the pregnant pig’s health or the farmer’s bottom line.   

“Today there is no single housing system that guarantees good sow welfare,” says Thomas Parsons, director of the Swine Research and Training Center. “The goal of our research is to improve pen gestation in order to maximize animal welfare and insure a financially viable future for pig farmers.” 

At the research center, dominant sows still bully others, but attention to pen size, shape and layout help minimize these aggressive tendencies. These dominant sows also can no longer deny others access to food, thanks to a technological innovation. That is because instead of the pigs getting food from an open trough, food is dispensed in automatic feeders large enough for just one pig at a time. When a sow enters a feeding station — picture a photo booth — a radio-frequency tag attached to her ear activates the computer-controlled dispenser. The computer system tracks how much food has been dispensed and will stop after a sow has reached her daily limit, ensuring that each sow gets exactly the right amount of food every day.   

The feeding stations also contain scales that can record the sow’s weight and how evenly it is distributed; an uneven distribution is an early indication of a leg injury. The ear tags also allow researchers to digitally manage the herd, tracking vaccinations, pregnancies, and the pigs’ locations within the facility. This gives researchers a better sense of the sows' preferences for where they spend their time, including when they cross into the facility’s outdoor area.

This data-driven approach to housing and feeding, coupled with hours of meticulous observation, allows researchers to better understand the lives of their pigs and the degree to which open housing actually improves their welfare. With the legally mandated transition away from gestational crates culminating in Europe next year and humane farming methods increasingly factoring into consumer choices, this data could not be more timely.

Originally published on May 17, 2012