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Number born alive accuracy changes by including crossbred records when estimating Large White and Landrace breeding values from a large seedstock supplier
Swine breeding companies utilize purebred performance records to estimate breeding values by traditional quantitative methods. Some have access to crossbred progeny performance records from client herds. Increased selection accuracy, which results in improved genetic progress, can be obtained by increasing the number of records for an individual or its relatives. The objective of this study was to estimate the change in prediction accuracy for purebred Large White (LW) and Landrace (LR) animals when using field data from crossbred progeny for numbers born alive. Data were obtained from a large pig breeding company and consisted of 603,606 sow records, of which 319,253 were purebred sow records. This included records from company nucleus farms, company multiplier farms, client daughter-nucleus farms, and client-owned closed herd commercial farms. Breeding values and prediction accuracies for number born alive were estimated for all animals using best linear unbiased prediction. The number of purebred LR and LW sows in the dataset was 78,619, of which 17,147 were company owned and 49,899 were client owned. The percent of purebred sows with pedigree information was 99% in company nucleus herds, 87% in client daughter-nucleus herds, 87% in client-owned closed herds, and 45% in company multiplier herds. The number of crossbred sows in the dataset was 72,704, of which 34% had pedigree information. Three client herds with pedigree information on more than 70% of their LR/LW crossbred sows were used for accuracy comparisons. Change in accuracy and Pearson correlations between different accuracy estimates with and without crossbred daughter records were calculated for active purebred sows. For sows with 0 daughter records, the increase in accuracy was 0.001 ± 0.001; and the correlation between accuracy estimates was 1.00. For sows with 1–9 crossbred daughter records, the increase in accuracy was 0.09 ± 0.04; and the correlation between accuracy estimates was 0.59. The increase in accuracy for sows with 10–19 crossbred daughter records was 0.16 ± 0.04, and the correlation between accuracy estimates was 0.40. For sows with >20 crossbred daughter records, the increase in accuracy was 0.23 ± 0.03 with a correlation between accuracy estimates of 0.71. These results suggest that including crossbred daughter records increases the selection accuracy in purebred sows with daughter litter records; and the magnitude of this increase in accuracy implies that the potential exists to impact selection and mating decisions, resulting in increased genetic progress.
Keywords: Accuracy, Breeding Value, Number Born Alive