Walloon strategies targeting new traits for efficiency, mitigation, adaptation and resilience in dairy cattle

Abstract

The transition towards sustainable dairy production requires the development and implementation of novel traits addressing environmental impact, resource efficiency, animal welfare, adaptation, and resilience. In the Walloon Region of Belgium, these developments are supported by long-term investments in milk mid-infrared (MIR) phenotyping, routine milk recording, genomic evaluation infrastructure, and digital data integration. The objective of this paper is to present a unified framework enabling rapid implementation of novel traits into routine genomic evaluations. The proposed framework relies on predicting novel phenotypes from routinely collected MIR milk spectra, followed by genomic evaluation using existing random regression single-step genomic BLUP (RR-ssGBLUP) procedures originally developed for production traits. Methane emissions predicted from MIR spectra (PCH4) represent the first trait already implemented in routine evaluations. The methane evaluation currently includes more than 4.5 million test-day records from over 328,000 Holstein cows and 9,631 genotyped animals. Genomic breeding values and methane efficiency indexes are routinely generated. The same framework is currently being expanded towards adaptation and resilience traits. A recent example is Heat Stress Response (HSR), developed from MIR-based phenotypes generated from data collected during periods of thermal challenge. Genomic evaluations resulted in heritability estimates of approximately 0.10 and generated more than 6,700 genomic breeding values with moderate to high reliabilities. Preliminary analyses indicate favorable opportunities for selection aimed at improving heat tolerance while maintaining productive performance. Additional developments include welfare-related traits, feed efficiency indicators, nitrogen use efficiency, and the integration of sensor-derived information through the WALLeSmart digital platform. These developments demonstrate that routine phenotyping infrastructures can support rapid deployment of novel sustainability traits. The presented strategy illustrates how a common genomic evaluation architecture can accelerate implementation of emerging traits and facilitate future international collaborations and genomic exchange.