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I am a co-author of papers published in the Journal of Animal Science by Moeller et al. (2004) and Serenius et al. (2006) that report data from the National Pork Producers Council Maternal Line Evaluation project (MLE). In his letter to the editor, DeBuse (2007) claims that the authors of these papers misrepresented the line submitted by Newsham Hybrids (USA) Inc. (NH; Colorado Springs, CO) to the MLE. Below are the facts, as I know them, regarding the design and implementation of the MLE.
The MLE tested crossbred females that represented maternal lines available to producers. It was designed to detect differences between lines for longevity traits, with probabilities of type 1 and type 2 errors of 0.05 and 0.75, respectively, requiring 531 females per line. The number of sires depended on the effective population size of the nucleus populations. Each participant was required to submit a minimum of 590 gilts per line to assure 531 breeding gilts. To assure that the nucleus populations were materially closed, 90% of the litters born during the last 5 years were required to have a sire that was born within the population, and 90% of the litters were required to have a dam that was born in the population.