Swine

Rethinking longevity: The boar perspective

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Abstract

Longevity in swine has traditionally been studied in sows, while limited attention has been given to boars. In boar studs, although short generation intervals are desirable to accelerate genetic progress, reducing involuntary removals can improve the return on genetic investment, lower replacement costs, and ensure a more consistent semen supply. In this context, boar longevity refers to the ability of a boar to remain in the stud until a voluntary replacement decision is made, rather than being prematurely removed for undesirable reasons. We aimed to estimate genetic parameters and evaluate genomic breeding values (GEBV) for boar longevity, considering three main involuntary removal reasons: Structure, Reproductive, and Other. The Structure included removals related to lameness, the Reproductive category encompassed removals due to semen quality, libido, or other reproductive issues, and the Other category grouped health problems, euthanasia, death, or unknown causes. Boar longevity was defined as the number of days the animal remained in the stud before removal. The phenotypes for Structure (N= 4,724), Reproductive (N= 4,027), and Other (N= 6,648) reasons were analyzed using a multi-trait animal model, in which the animal effect corresponds to the phenotyped boar. The model included fixed effects and the random effects of contemporary group and animal genetics. GEBV were estimated using ssGBLUP with the algorithm for proven and young with 5k core animals. Prediction accuracy was assessed using the Linear Regression (LR) method, which compared GEBV from validation and reference populations. In the partial datasets, phenotypes of 1,260, 1,044, and 1,428 boars were omitted for Structure, Reproductive, and Other, respectively. Table 1 shows a summary of the results, including genetic parameters and LR validation metrics. Heritability estimates for boar longevity by removal reason were 0.12 ± 0.03, 0.05 ± 0.02, and 0.05 ± 0.02 for Structure, Reproductive, and Other reasons, respectively. Genetic correlations among removal reasons ranged from 0.43 ± 0.19 to 0.71 ± 0.40. In the LR validation, an ideal model has a level bias close to 0, a regression coefficient (b1) near 1, and, when comparing models, higher accuracy values indicate better predictive performance. Bias ranged from -0.02 to 0.00 and b1 from 0.78 to 0.87, suggesting a slight underestimation of GEBV in the partial dataset for the animals removed for Structure and Reproductive reasons. Accuracies, ranging from 0.30 to 0.34, indicated consistent predictivity across removal reasons. These findings suggest that boar longevity is heritable and moderately correlated across removal causes. Accounting for specific removal reasons provides a more comprehensive understanding of the genetic determinants of longevity in breeding males. Incorporating this information into selection programs may enhance boar retention, reduce replacement costs, and improve overall stud efficiency.

Keywords: 2026

How to Cite:

Garcia, A., Chen, C., Holl, J., Misztal, I. & Lourenco, D., (2026) “Rethinking longevity: The boar perspective”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2284654. doi: https://doi.org/10.31274/wcgalp.23607

Rights: 1