Phenomics

Does Drying Matter? Evaluating NIR Accuracy for Protein Digestibility in Pig Feces

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Abstract

Protein efficiency in livestock production is becoming increasingly critical as the cost of dietary protein and nitrogen-emission regulations continue to rise, while genetic progress in protein deposition (PD) increases the nutritional demands of modern genotypes. Genetic selection for improved apparent total tract digestibility of protein (ATTD_CP) offers a promising strategy to reduce feed costs and mitigate environmental impacts. ATTD_CP can be predicted using Near Infrared Reflectance (NIR) spectroscopy on feed and fecal samples, and the trait is heritable. For integration into breeding programs, phenotyping must be non-destructive, objective, accurate, cost-effective, and available at the time of selection. Using fresh fecal samples for NIR analysis provides logistical and economic advantages, but the influence of moisture on measurement accuracy remains unclear, as does the impact on estimated breeding value (EBV) accuracy. In this study, 307 fecal samples from selection candidates of sire and dam lines at the Topigs Norsvin central boar testing facility (Canada) were collected pre-off-test. Each fecal sample, along with a corresponding feed sample, was chemically analyzed, and NIR spectra were obtained from both fresh and dried feces. Calibration accuracy was assessed using Leave-One-Out cross-validation, and calibration curves were subsequently applied to the spectra of all animals to derive predicted ATTD_CP phenotypes. Prediction accuracy (r) was 0.76 for fresh fecal samples and 0.88 for dried samples. Heritability estimates were similar (p >0.05) between sample types, at 0.27 for fresh and 0.24 for dried samples. These results suggest that although dried samples provide higher prediction accuracy, fresh samples yield comparable heritability estimates and may therefore serve as a practical alternative for large-scale genetic evaluation.

Keywords: 2026

How to Cite:

Bergsma, R., Lei, V. & Rodas-Gonzales, A., (2026) “Does Drying Matter? Evaluating NIR Accuracy for Protein Digestibility in Pig Feces”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286548. doi: https://doi.org/10.31274/wcgalp.24045

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