healthy cows eat grass and make methane

20.5.14: pol/purges/climate change
/healthy cows eat grass and make methane:
Israeli Researchers Cut Air Pollution
by Reducing Gas Output from Cows
[Judy Siegel-Itzkovich 2020 May 14]
. the author of this news supposes that
if a researcher studies the origin of cow germs
(diet vs germs given by mother)
it must be to control a greenhouse gas,
but I couldn't find such a concern
mentioned in the reference;
and, that is as it should be; because,
healthy, happy cows eat grass not grains;
and fermenting grass makes a lot of methane.

When cattle were grazed on pasture [grass],
cows produced .23 kg methane /animal/day
(7.7-8.4% of gross energy for methane).
the same cattle fed a high-grain diet,
produced only .07 kg methane /animal/day
(1.9-2.2% of the feed energy for methane).
[Harper; Denmead; Freney; Byers J. Anim. Sci. 1999:
Direct Measurements of Methane Emissions
from Grazing and Feedlot Cattle]

I doubt there is any type of replacement germ
that can ferment grass without making methane;
if so, the only cow-friendly solution
is to either need fewer cows
or adapt to climate change rather than
trying to control the weather.

scholar search for
Nature Communications, Eran Halperin 2020:

the subject of this news is here:

Stochasticity constrained by deterministic effects of diet and age
drive rumen microbiome assembly dynamics
…, S Jacoby, T Hertz, OX Cordero, E Halperin… - … communications, 2020 - nature.com
How complex communities assemble through the animal's life, and how predictable the process is remains unexplored. Here, we investigate the forces that drive the assembly of rumen microbiomes throughout a cow's life, with emphasis on the balance between stochastic and deterministic processes.

there is another search result about
ways to test the cows' germs:

Accurate estimation of cell composition in bulk expression
through robust integration of single-cell information
…, KH Pietiläinen, P Pajukanta, E Halperin - … Communications, 2020 - nature.com