Heritability estimates for enteric methane emissions from Holstein cattle measured using noninvasive methods.

Area of Science:

• Animal Genetics and Breeding
• Environmental Science
• Dairy Science

Background:

• Enteric methane (CH4) emissions from dairy cattle contribute to greenhouse gas output.
• Understanding the heritability of CH4 emissions is crucial for developing mitigation strategies.
• Previous research has explored factors influencing CH4 production, but genetic control requires further investigation.

Purpose of the Study:

• To estimate the heritability of enteric methane emissions in Holstein dairy cows.
• To investigate the genetic correlations between different CH4 emission phenotypes and milk production traits.
• To assess the potential for genetic selection to reduce CH4 emissions in dairy cattle.

Main Methods:

• Methane (CH4) and CO2 were measured using a portable Fourier transform infrared analyzer.
• Data were collected from 3,121 Holstein cows across 20 herds with automatic milking systems.
• Univariate and bivariate linear animal models were used to analyze CH4_RATIO, CH4_GRAMSw, CH4_MILK, fat- and protein-corrected milk (FPCM), and live weight.

Main Results:

• Heritability estimates for CH4_GRAMSw and CH4_MILK were 0.21 (SE 0.06), and for CH4_RATIO was 0.16 (SE 0.04).
• Strong genetic correlations were found between CH4_GRAMSw and CH4_RATIO (rg=0.83), and with FPCM, indicating selection for milk yield may increase CH4 per cow.
• Genetic correlations between CH4 phenotypes and live weight were low and not significantly different from zero.

Conclusions:

• Enteric methane emission in dairy cattle is partly heritable, suggesting potential for reduction through genetic selection.
• Selection for increased milk production is likely to increase methane emissions per cow.
• Breeding programs should consider the genetic relationship between milk yield and CH4 emissions to achieve dual goals of productivity and environmental sustainability.