Inside Iowa State

February 11, 2005

Software calculates sow longevity

by Anne Krapfl

A customized spreadsheet distributed by ISU's Iowa Pork Industry Center helps pork producers and breeders around the world raise pigs more efficiently.

Developed by assistant animal science professor and Extension swine specialist Ken Stalder and a colleague while at the University of Tennessee, the free software calculates the minimum time a breeding sow (gilt) should remain in a herd -- that is, until she pays for herself. To date, it has been used to track more than 15 million sows in 28 countries.

"The replacement rate for gilts in many commercial farms is getting high," Stalder said. "With this spreadsheet, we're trying to get managers to think differently and manage their herds differently. There are financial benefits to be gained from a sow staying in a herd, as long as she continues to be productive."

To use the software, a producer keys in data such as price paid for a gilt, feed costs and anticipated sale prices for the pigs that sow produces. The software calculates how many litters a sow has to have to recoup its purchase price, as well as how that figure might fluctuate (for example, as market prices move up and down). Stalder said the average investment in Iowa to purchase a gilt and appropriate vaccinations is about $250.

The Sow Longevity Calculator is available in four versions, for use with either pounds or metric measure-ments, and in each of two cycles: birth to slaughter (known as "farrow to finish") or breeding to weaning (in cases when pigs are sold as soon as they're weaned).