Estimation & Prediction

Integrating Growth Curve Analysis and Genetic Architecture: Pathway to Improved Breeding Decisions for Sow Longevity

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Abstract

Efficient gilt development is essential for maximizing sow herd productivity, yet the biological signals that guide early breeding decisions remain poorly understood. Growth curve modeling highlights the inflection point (IP), where the growth rate begins to slow as gilts transition towards physiological maturity. This turning point reflects the balance between body weight gain and reproductive readiness, making it a key indicator of the timing of first breeding. This study evaluated the growth-curve inflection point as a marker of physiological maturity, its relationship with first breeding and parity one (P1) litter size, and its underlying genetic architecture. Growth data from 2,876 gilts, including 1,454 Large White and 1,422 Landrace females, raised in a Hypor nucleus barn in Saskatchewan, Canada, between 2023 and 2025. Individual growth trajectories were modeled per breed using the Gompertz function. The IP estimates were evaluated against P1 litter size traits, including total born (TB, median 15.0) and born alive (BA, median 13.0). Generalized linear mixed models were implemented in R (v4.5.1) to test the effect of the IP on P1 outcomes. Additional females from 2021-2022 were incorporated for genetic parameter estimation using BLUPF90+ with restricted maximum-likelihood (REML). Following quality control, 14,954 variants and 2,295 animals remained for Large White, while 14,944 variants and 2,502 animals were retained for Landrace. Genome-wide association studies (GWAS) were conducted using GCTA (v1.93.2) to identify genomic regions associated with Gompertz parameter traits. Despite similar growth rates, gilts reaching their inflection point at a younger age (111.42 days) and at a lighter body weight (67.77 kg), with a maturation rate of 2.26 (150 days⁻¹), showed higher P1 litter size for TB (15.27) and BA (13.85). In contrast, gilts with a later inflection point (176.56 days) and heavier body weights (119.86 kg) with a maturation rate of 1.05 (150 days⁻¹) showed reduced P1 litter size for TB (12.76) and BA (11.73). Heritability (h2) estimates for reproductive traits were low (Landrace, h2 = 0.19±0.04; Large White, h2 = 0.11-0.13 ±0.03). IP traits exhibited low heritability for the Landrace breed (0.02-0.06±0.04) and low to moderate heritability for the Large White breed (0.17-0.27±0.07). GWAS identified SSC1, SSC7, SSC8, and SSC11 as regions of interest for growth and development. Overall, the IP represents a key biological transition toward reproductive maturity. Aligning gilt selection with physiological maturity can improve early reproductive success and enhance longevity.

Keywords: 2026

How to Cite:

Allen, S., Patterson, J., DeVries, B., Charagu, P., Bink, M., Huisman, A., Dyck, M. & Plastow, G., (2026) “Integrating Growth Curve Analysis and Genetic Architecture: Pathway to Improved Breeding Decisions for Sow Longevity”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2287105. doi: https://doi.org/10.31274/wcgalp.24211

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