Pork producers now have new versions of two spreadsheets that can help determine optimum times for keeping sows in their operations. The Sow Longevity Calculators Version 2.00 for farrow-to-finish operations and for breed-to-wean operations works with Microsoft Excel 97 or newer versions, and they're available in English and metric options.
All versions are available at no charge via e-mail from the Iowa Pork Industry Center at Iowa State University, by simply completing an online registration form. To do so, go to http://www.extension.iastate.edu/ipic/subjects.html, choose  “Management/Economics” from the listing at the top of the page; then choose the appropriate Sow Longevity Spreadsheet entry from that section.
Ken Stalder, Iowa State Extension swine specialist, and Curt Lacy, University of Georgia Extension economist, have updated both spreadsheets to provide even more information. Stalder points out that the new versions allow input for actual herd size while adjusting for parity performance differences. This provides more accurate results for any particular herd.
“Both are outstanding tools for determining how long a sow needs to remain in the breeding herd to reach positive net present value,” says Stalder. “They use operation-specific production and financial information, so individual producers can determine how long sows must remain in their herds to create a positive net value.”
The programs provide producers with a net present value analysis that helps provide an economic overview of their operations. If the NPV is greater than zero, the gilt investment should be profitable in the long term. If the NPV is less than zero, the investment in the gilt will not be profitable in the long term.
“By using the program appropriate for their operation, producers can focus on management practices that improve sow longevity in their herds, and improved longevity can increase profitability,” he notes.