industry
taking carbon that has been stored in the earth
since pre-historic times and converting it to “new”
carbon dioxide released to the atmosphere. For
every gallon of fuel consumed, about 20 pounds
of carbon dioxide are created and released to the
atmosphere. We are releasing this gas more rapidly
than it can be absorbed in our oceans and soils.
Thus, we are observing a rather rapid increase
in atmospheric carbon dioxide concentration,
and the effect of this change will be with us
for 1000s of years. Whereas cattle are part of a
natural cycle with short-term impact, burning
of fossil fuels has a more permanent impact.
Cattle numbers and greenhouse gas emissions
We must also consider the number of cattle and
their productivity. Cattle numbers in the United
States have been stable or declining for many
years. Beef cow numbers peaked in 1975, and
the current number is similar to that maintained
in the early 1960s. Dairy cow numbers are the
lowest they have been in over 100 years.
We also have to consider that modern cattle
are getting larger and more productive. They
consume more feed and produce more methane
per animal, but they are also more efficient
producing more meat or milk per unit of feed
consumed. Considering cattle numbers and
these increases in productivity and efficiency,
methane emission from cattle in the United
States has not increased over the past 50 years.
This is recent history; what if we look further
back? Ruminant wildlife were prevalent in North
America before European settlement. Although
there are not accurate numbers for the buffalo,
elk, deer, and other ruminants on the continent
at that time, estimates are available. Based
upon those estimates, these animals produced
methane in the range of 50% less to 25% more
than the current population of cattle, other
farm ruminants and wildlife. This indicates that
cattle today are not contributing a substantial
increase in the methane emissions from U.S.
lands compared to pre-settlement times.
So what might be increasing methane
concentration in the atmosphere? Global cattle
numbers are increasing. Methane is also released
during the extraction, refining, and transport
of fossil fuels. This methane also oxidizes in
the atmosphere to form carbon dioxide, but
this is not part of a natural cycle. Like the
combustion of fuels, this removes carbon stored
in the earth to create new carbon dioxide in
the atmosphere with very long-term effects.
Can cattle be part of the solution?
The fact remains that cattle produce a lot of
methane. This methane is essentially wasted
energy escaping the rumen. Reducing this waste
by increasing the efficiency of the rumen may
provide a substantial benefit by producing more
meat or milk with less feed consumed. Dietary
changes can reduce enteric methane production,
and feed supplements are being explored to
improve feed efficiency and reduce emissions.
Depending upon the cost of dietary changes
and supplements, these interventions may
provide economic benefit to the producer. In
addition, there is the possibility of claiming
carbon credits for this reduction. Companies
and other institutions desiring to reduce their
carbon footprint may be willing to pay cattle
producers to use these mitigation practices.
This is largely in the future for now.
So, although cattle in the United States are not
causing an increase in global warming and related
climate change, they may become part of the
solution. Reducing any source of greenhouse
gas emission will benefit our planet. LT
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