Methane profiles assessment in growing Simmental bulls with divergent feed efficiency

Area of Science:

• Animal Science
• Environmental Science
• Genetics

Background:

• Genetic selection in livestock aims to reduce environmental impact.
• Methane (CH4) production is linked to animal feed efficiency.
• Laser methane detectors (LMDs) offer a practical method for in vivo CH4 quantification.

Purpose of the Study:

• Characterize the CH4 profile of growing Simmental bulls using LMD.
• Relate CH4 production metrics to feed efficiency (Residual Feed Intake - RFI).
• Investigate if more efficient animals produce less CH4.

Main Methods:

• Analyzed 1164 CH4 profiles from 194 Italian Simmental bulls using LMD.
• Assessed CH4 peak characteristics (type, number, intensity).
• Compared CH4 production (total, yield, RME) between high and low RFI groups.

Main Results:

• No significant differences in total CH4 peaks or eructation traits between efficiency groups.
• CH4 production in g/day was similar between high and low efficiency bulls.
• Methane yield (g/kg DMI) and residual methane emission (RME) were higher in high-efficiency bulls.

Conclusions:

• Total CH4 production is not necessarily lower in more feed-efficient animals.
• Highly efficient animals may have a less favorable CH4 footprint when considering methane yield and RME.
• Findings challenge assumptions about the environmental benefits of selecting for feed efficiency.