Friend or Food?

Pressing the bar enough times brings a little snack one day, socializing with neighbors the next day. So far, pregnant pigs are choosing the snacks.

Scientists have often compared pregnant pigs in different housing situations. But now scientists from the Agricultural Research Service (ARS) and Purdue University are asking the moms-to-be for their preferences.

Researchers set up a study with 16 pregnant pigs, studying four at a time. They put each animal in a conventional gestation stall designed to confine pregnant pigs--but also added a control bar. On one day the pressing the bar rewards the pigs with a snack - on the next day it opens a door to allow a visit with other pigs. This goes on for several days, with the number of required bar presses increasing each day.

The pigs' would press the bar with their snouts for a reward about the same number of times for the food treat as they would to socialize.  This indicates that socializing wasn't anything special to them.

The next round of experiments will show if pigs refine their choices in a more "homey" environment--one where there's more to do, a soft floor and plenty of straw to satisfy instincts for nesting or rooting.

This research was published in the March 2005 issue of Agricultural Research magazine.

Bjorn Carey

Credit: Peggy Greb