Selecting for Feed Efficient Cows Will Help to Reduce Methane Gas Emissions

Abstract

In the last decade, several countries have included feed efficiency (as residual feed intake; RFI) in their breeding goal. Recent studies showed that RFI is favorably correlated with methane emissions. Thus, selecting for lower emitting animals indirectly through RFI could be a short-term strategy in order to achieve the intended reduction set by the EU Commission (-55% for 2030). The objectives were to 1) estimate genetic parameters for six methane traits, including genetic correlations between methane traits, production, and feed efficiency traits, 2) evaluate the expected correlated response of methane traits when selecting for feed efficiency with or without including methane, 3) quantify the impact of reducing methane emissions in dairy cattle using the Danish Holstein population as an example. A total of 26,664 CH4 breath records from 647 Danish Holstein cows measured over 7 years in a research farm were analyzed. Records on dry matter intake (DMI), body weight (BW), and energy corrected milk (ECM) were also available. Methane traits were methane concentration (MeC, ppm), methane production (MeP; g/d), methane yield (MeY; g CH4/kg DMI), methane intensity (MeI; g CH4/kg ECM), residual methane concentration (RMeC), residual methane production (RMeP, g/d), and two definitions of residual feed intake with or without including body weight change (RFI1, RFI2). The estimated heritability of MeC was 0.20 ± 0.05 and for MeP, it was 0.21 ± 0.05, whereas heritability estimates for MeY and MeI were 0.22 ± 0.05 and 0.18 ± 0.04, and for the RMeC and RMeP, they were 0.23 ± 0.06 and 0.16 ± 0.02, respectively. Genetic correlations between methane traits ranged from moderate to highly correlated (0.48 ± 0.16–0.98 ± 0.01). Genetic correlations between methane traits and feed efficiency were all positive, ranging from 0.05 ± 0.20 (MeI-RFI2) to 0.76 ± 0.09 (MeP-RFI2). Selection index calculations showed that selecting for feed efficiency has a positive impact on reducing methane emissions’ expected response, independently of the trait used (MeP, RMeP, or MeI). Nevertheless, adding a negative economic value for methane would accelerate the response and help to reach the reduction goal in fewer generations. Therefore, including methane in the breeding goal seems to be a faster way to achieve the desired methane emission reductions in dairy cattle.

Phenotypic relationship and repeatability of methane emissions and performance traits in beef cattle using a GreenFeed system

“…Additionally, RCH 4 had non-significant relationships with muscle scanning traits and carcass traits, which was explained by the relationship of these traits to DMI and LW. Residual CH 4 presents some difficulty in relation to interpretability ( Manzanilla-Pech et al, 2022 ), similar to ratio traits. End user interpretability of a CH 4 trait is paramount to utilization and has presented some obstacles with residual feed intake ( Manzanilla-Pech et al, 2022 ).…”

“…Residual CH 4 presents some difficulty in relation to interpretability ( Manzanilla-Pech et al, 2022 ), similar to ratio traits. End user interpretability of a CH 4 trait is paramount to utilization and has presented some obstacles with residual feed intake ( Manzanilla-Pech et al, 2022 ). The use of phenotypically derived RCH 4 phenotypes in genetic evaluations may be problematic at a practical level where one or other of the underlying traits is unavailable.…”

Technology for Carbon Neutral Animal Breeding

“…However, putting a negative economic value on methane would encourage action and help to reach the reduction goal in fewer generations. Therefore, it seems that including methane in the breeding objective will aid dairy cattle in more quickly reducing their methane emissions [7].…”

Different microbial genera drive methane emissions in beef cattle fed with two extreme diets

“…Methane is an unnecessary by-product of microbial fermentation of mainly complex carbohydrates in the rumen, synthesized by methanogenic archaea and released into the environment through the animal’s mouth and nose. Eructated methane from ruminal microbial fermentation not only contributes to global warming, but also results in unnecessary loss of energy, compromising feed efficiency ( Manzanilla-Pech et al, 2022 ). Because the microbiome plays a key role in the synthesis of methane, most methane mitigation strategies in ruminants rely on altering the rumen conditions and microbial ecology.…”