Disease & heat resistance

Genetic variation of resilience indicators and their associations with functional traits in Nordic Red dairy cattle

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Abstract

Due to challenges of intensive dairy farming and increasing emphasis on animal health and welfare in breeding programs, resilience is becoming an important selection trait. Resilience is a composite trait. It cannot be measured directly and there are no breeding goals that include resilience per se globally. Milk yield and deviations from lactation curves have been used to identify resilience indicator traits (RITs). Their accuracy and use as goal traits depend on how closely they are associated with functional and health traits. Such correlations and the genetic basis of RITs in the Nordic Red dairy cattle are largely unknown. The aims of this study were to assess the genetic variation of RITs and estimate their associations with fertility and health traits using data from milking robots. Data were from 2017-2019 and included cows with records in at least 280 days between 6 and 305 days in milk from the first three lactations. The final dataset had six million observations from 20,500 cows and pedigree including 84,490 animals. Smoothing and curve fitting methods were used and eleven RITs were identified including: NDDI, number of deviations detected; LLac, total performance loss during lactation; Lpert, performance loss during a perturbation; MAUC, average of area under the curves; MΔT, average duration of deviation detected; MTcol, average of collapse phase time by deviation; MTrec, average of recovery phase time by deviation; MML, average of maximum performance loss during deviation; LnVar, natural log-transformed variance of deviations from a lactation curve; rauto, lag-1 auto-correlation of deviations from a lactation curve and ADMY, average daily milk yield. The fertility and health traits considered were interval from calving to first service, interval from first to last service, number of inseminations, conception rate, and lactation average somatic cell score. Univariate and bivariate repeatability animal models were applied. Models fitted fixed effects of parity, year×season of birth, herd×year of calving, year×season of calving, year×month of insemination, fixed regression on age at calving, heterosis, inbreeding and random permanent environment, animal genetic and residual effects. Variance components were estimated by Monte Carlo Expected Maximization REML using MiX99 software. The heritabilities of RITs ranged from 0.03-0.35 and specifically were 0.17±0.02, 0.07±0.01 and 0.11±0.01 for LnVar, rauto and LLac, respectively. The genetic associations among RITs differed and were lowest between LnVar and rauto (0.01±0.10) and highest between LnVar and MAUC (0.79±0.05). Genetic correlations of LnVar, ADMY and LLac with fertility and health traits ranged from -0.12-0.32, -0.16-0.19 and 0.07-0.32, respectively. Of all RITs identified, these three indicators have low to moderate heritabilities and close associations with health and fertility traits. This indicates their potential as goal traits highlighting their ability to respond to selection when included into Nordic Red dairy cattle breeding plans.

Keywords: 2026

How to Cite:

Chegini, A., Kavlak, A., Kempe, R., Lidauer, M., Negussie, E., Pastell, M., Pitkänen, T. & Pösö, J., (2026) “Genetic variation of resilience indicators and their associations with functional traits in Nordic Red dairy cattle”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2283917. doi: https://doi.org/10.31274/wcgalp.23535

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