DES MOINES, Iowa -- Estimates regarding how many U.S. sows are housed in open pen gestation systems have varied widely. The Humane Society of the United States (HSUS) and some food companies tend to point to 30 percent of sows as the current industry level.
However, the National Pork Producers Council (NPPC) joined forces with University of Missouri agricultural economist Ron Plain to get a more accurate industry assessment. The team conducted an email survey touching on operations with 1,000 or more sows. The survey just wrapped up on Tuesday of this week and Plain reported the results at World Pork Expo today in Des Moines.
Plain referred to the survey as a "fast attempt" to determine the production level and the process took less than a month. "You can't survey all U.S. hog farms in that time," he said. So he opted for a representative sample. In the end, the survey involved 70 firms, and 3.6 million sows and breeding gilts. With an estimated 5.7 million sows in the U.S. breeding herd, that means the survey covered 62.6 percent of the herd. The survey respondents involved personnel who either owned or managed the sows.
"We asked what percentage of females are housed in open-pen gestation, which we defined as females that, once they were confirmed as pregnant, were housed in pens where they could not touch the sides," Plain reported. The overall average came up at 17 percent.
For a more precise breakdown, Plain indicted that for operations with 1,000 to 9,999 sows, 20.2 percent were in open-pen gestation at some point; for units with 10,000 to 99.999, it was 18.9 percent; and for herds with more than 100,000 sows, the rate was 16.4 percent.
The 17 percent average is slightly higher than the industry anticipated, which would have been in the 10 percent area.
The survey also asked what percentage might be housed in pens two years from now and the responses averaged 23 percent of the sows would be in pens, Plain added. Again, the levels broke down as 20.7 percent for systems with 1,000 to 9,999 sows; 21.3 percent for herds with 10,000 to 99,999; and 23.8 percent for the largest operations.
NPPC and Plain both emphasized that a lot of operations run some combination of pen and stall housing and the survey numbers do not mean that the sow was always housed in pen gestation, but rather that the animal spent some amount of time in a pen. Neither does the estimate mean that 17 percent of U.S. production comes from open-pen gestation.
"This is a very complex issue," said Dallas Hockman, NPPC's vice president of industry relations, "and the most dramatic one in my 30 years in the industry." He noted that pork producers conducted the survey in order to "bring forth the facts," regarding the availability and potential supply of pork from systems not tied to getstation-sow stalls.