Breeding for reduced methane emission and feed-efficient Holstein cows: An international response

Area of Science:

• Animal Science
• Genetics
• Environmental Science

Background:

• Genetic selection for lower methane (CH4) emissions is permanent and cumulative.
• Combining international data can improve genetic parameter accuracy for CH4 traits.
• Understanding genetic correlations between CH4 and production traits is vital for breeding goals.

Purpose of the Study:

• Estimate genetic parameters for seven CH4 traits.
• Determine genetic correlations between CH4 and production, maintenance, and efficiency traits.
• Evaluate the impact of including CH4 traits in breeding goals on economically important traits.

Main Methods:

• Analyzed 15,320 methane production (MeP) records from 2,990 cows across four countries.
• Included data on dry matter intake (DMI), body weight (BW), and milk yield (MY).
• Calculated various methane traits including methane yield (MeY), methane intensity (MeI), and residual methane traits.

Main Results:

• Heritability estimates for MeP, MeY, and MeI were 0.21, 0.30, and 0.38, respectively.
• Moderate to high genetic correlations (0.41-0.97) were found between different CH4 traits.
• Residual methane traits showed the most promise for breeding goals, with favorable correlations with residual feed intake.

Conclusions:

• Residual methane traits are suitable for breeding goals, enabling selection for lower emissions without compromising economic traits.
• Incorporating residual feed intake can further reduce methane emissions.
• Adding a negative economic value for methane can significantly decrease emissions while maintaining milk production.