Cameras Catch Pigs in the Act

Research conducted by a graduate student at Iowa State University (ISU) has shown that digital images provide a more accurate measurement of pig behavior than human observation.

ISU graduate student Shawna Weimer says plans that date back to 2003 by the National Pork Board to assess pig behavior by approaching piglets was eventually rejected because people observing piglets could not get consistent results.

“There is a need for these measures to be objective, repeatable and reliable,” Weimer says.

In her talk at the Midwest meeting of the American Society of Animal Science this week in Des Moines, IA, Weimer reviewed a study of nursery pigs. She found that digital imaging can be a more reliable way of assessing welfare and willingness of pigs to approach a human.

To compare human observation with digital imaging, she assessed pig behavior at the exact same time as a camera took a photo. Weimer entered pens and then crouched on the floor. She looked down for 15 seconds in a non-threatening posture for pigs and then up to visually assess where the piglets were in the pen. When she looked up, she also used a remote control to take a photo with a camera fixed several feet above her.

While crouching in the pen, she recorded the number of pigs making physical contact with her, making eye contact with her or doing neither. She noted the position of pigs not making physical or eye contact. “Only piling would be considered a fearful behavior,” she says.

After the live observations, Weimer analyzed the images of the pens for the same behaviors and used this method to assess 79 pens of 23, six-week-old piglets. She found that digital images recorded more accurate measurements of pig behavior than human observation.

The study found that the limited field of human vision and limited time in the pen impacts observations of pigs to humans. Weimer says consistent measurements of pig behavior can help producers reduce pig stress.

The information for this article appeared in the American Society of Animal Science newsletter found at



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