Next steps towards the development of a collaborative genomic evaluation system for residual methane production in Walloon Holstein cows

Authors

  • Hadi Atashi
  • Yansen Chen
  • Amélie Vanlierde
  • Frédéric Dehareng
  • Hélène Soyeurt
  • Nicolas Gengler

Abstract

Greenhouse gases emissions from ruminants are one of the causes of climate change. Methane (CH4) from dairy cows is a major greenhouse gas and is also associated with the energy use efficiency in dairy cows. This study aimed to use data of CH4 emissions (PME, g/d) predicted using the recorded milk mid-infrared (MIR) spectra to develop a genomic evaluation system for CH4 of Holstein cows in the Walloon region of Belgium. The preliminary relationships among predicted CH4 (PCH4, defined as the estimated breeding value for PME), expected CH4 (ECH4, estimated based on production traits), residual CH4 (RCH4) [defined as PCH4- ECH4] and MACE traits and local indices were also investigated. The data of PME predicted between 2007 and 2023 on Walloon Holstein cows were used. The number of used test-day records (cows) was 2,129,225 (319,301), 1,675,056 (250,707), 1,184,377 (178,882) for the first, second, and third lactation, respectively. Genotypic data on 28,317 SNPs were available for 18,378 (3,887 sires) animals. The EM-REML method was employed to estimate the variance components. Mean (SD) daily PME per cow was 324 (68) g/d, 353 (71) g/d, and 367 (73) g/d for the first, second, and third lactation, respectively. Mean (SD) heritability estimates for daily PME were 0.13 (0.04), 0.13 (0.04), and 0.14 (0.04) in the first, second and third lactation, respectively. The average reliability of PCH4 for the selected bulls was 70% and ranged from 51% to 98%. The corresponding value for RCH4 was 71% and ranged from 50 to 98%. The ECH4 was estimated for 1,170 selected international sires using available GEBV of milk, fat, and protein yields as: ECH4 = b1GEBVMY + b2GEBVFY + b3GEBVPY. The Pearson correlation of PCH4 and RCH4 was 0.83. PCH4 was correlated with production traits (from 0.16 to 0.51) while RCH4 was independent of them. The Pearson correlation among PCH4 with MACE traits and local indices ranged from 0.05 to 0.45, while the results of RCH4 ranged from -0.01 to 0.14. Our results suggest that an efficiency CH4 trait could be incorporated into our current genomic evaluation systems, but our results also showed that definitions of methane efficiency solely on production traits can be dangerous.

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Published

2024-09-04

Issue

No. 60 (2024): Proceedings of the 2024 Interbull Meeting

Section

Articles

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