Methane and Genetics: Can Selective Breeding Produce Lower-Emitting Holstein Cows?

Why breeders are asking

Feed, manure and methane all show up in a dairy's environmental footprint, and methane from the rumen is a large part of the enteric piece. Nutrition and additives get most of the attention, but they work only while you keep feeding them. Genetics works differently. A genetic change is permanent and cumulative, passed from every sire and dam to every calf that follows. That is why researchers have spent the last several years asking whether some Holsteins naturally make less methane, and whether breeders can use that variation.

What the heritability numbers say

The clearest recent Holstein analysis comes from Canadian researchers led by Flavio Schenkel at the University of Guelph. In a paper in Animals, they analyzed 1,765 methane records from 330 Holstein cattle in two Canadian herds and estimated heritability for three ways of expressing methane:

Trait	Heritability (standard error)
Daily methane production	0.16 (0.10)
Methane yield (per unit of feed intake)	0.27 (0.12)
Methane intensity (per unit of milk)	0.21 (0.14)

Those are moderate heritabilities, in the same general range as many traits breeders already select on. The standard errors are large because the data set is small, and the authors said so. They also reported strong genetic correlations among the three expressions, for example 0.94 between daily methane production and methane intensity. The abstract concludes that selecting for daily methane production would result in lower methane per unit of milk produced, though accuracy of the breeding values was low (0.32 to 0.44) and a larger data set is needed. Rankings of sires with daughters changed a lot depending on which trait was used, so which methane trait you choose matters.

In plain terms: the signal is real, but it is noisy, and the work is still early.

The measurement problem and the milk-spectra shortcut

Measuring methane on individual cows is expensive. Respiration chambers and breath-sampling systems cannot run on thousands of commercial animals. Researchers have therefore tried predicting methane from the mid-infrared spectrum of routine milk samples, which dairy herd improvement labs already collect. That is the approach behind the first national evaluation to reach producers.

Lactanet in Canada implemented a single-step genomic evaluation for methane efficiency in April 2023, described in JDS Communications. It uses milk mid-infrared predicted methane together with milk, fat and protein yields as correlated traits, then re-parameterizes so that the methane breeding value is genetically independent of production. It is expressed as a relative breeding value with a mean of 100 and a standard deviation of 5, and a higher value means lower predicted methane. The stated aim is to reduce methane without affecting production levels.

That design matters. A naive approach, selecting simply for lower daily methane, risks favoring cows that eat and produce less. Adjusting for yield asks a different question: among cows making the same milk, which ones emit less?

What this means for a U.S. herd

I could not find a methane trait in CDCB's published Net Merit trait history, so a U.S. breeder cannot currently pick bulls on an official methane figure the way a Canadian breeder can. What you can do depends on your goals.

1. Do not wait to improve efficiency. CDCB's published Net Merit history shows that residual feed intake and a body weight composite are part of the index, along with livability, fertility and health. Whether these track methane closely is not established here, but cows that convert feed to milk more efficiently are generally a sound goal on cost grounds alone.
2. Watch for trait announcements. If a methane or feed-efficiency evaluation arrives in your market, ask about reliability, how it handles yield, and whether it has been checked against measured methane in herds like yours.
3. Do not select on methane alone. Any new trait should sit inside a total-merit index. Our article on bull selection for the modern Holstein explains why single-trait chasing backfires.
4. Keep records clean. Parentage, test-day records and milk samples are the raw material for any future evaluation, and herds with good records will benefit first.

Limits and honest caveats

• Methane is heavily influenced by diet, so genetic differences are a modest slice of the total variation you would see in a herd.
• Milk-spectra predictions are indirect. Their accuracy depends on the reference data used to calibrate them.
• Genetic gains arrive slowly, over generations. Genetics complements feeding and management changes and does not replace them.
• Breeding values with low accuracy reshuffle quickly as data grows. Wait for reliable numbers before making large changes to a sire team.

The realistic picture

Selective breeding can plausibly produce lower-emitting Holsteins, because methane traits are moderately heritable and at least one country has put an official evaluation into practice. But the evidence base is small, the accuracy is modest, and the interaction with yield and health needs careful handling. For a U.S. herd today, the sensible path is to keep improving feed efficiency and overall merit, watch the research, and keep records good enough to benefit when evaluations mature. Related reading on the business side is available through the Agriculture Directory and farm.fm's farming section. This site is independent and not affiliated with any breed association or evaluation agency.