Bundoora, Victoria, Australia
May 5, 2008
Source:
Alpha Galileo
Grass that may help tackle global
warming by cutting the level of methane given off by cows is
being developed by scientists, reports the latest issue of the
Society of Chemical Industry’s (SCI) magazine Chemistry &
Industry.
Scientists at Gramina Pty.
Ltd.,
a joint biotech venture by Australia’s
Molecular Plant
Breeding Cooperative Research Centre and New Zealand rural
services group PGG
Wrightson Genomics, are developing a grass that will not
only cut the amount of methane cows burp up when chewing the cud
but also grow in hotter climes.
This means that farmers should be able to maintain dairy herds’
productivity and profitability in the face of a changing
climate, while cutting down their gaseous burps and reducing
their contribution to global warming.
Combating greenhouse gas emissions produced by the agricultural
industry is a priority. The UK’s DEFRA has just announced a
roadmap aimed at helping the dairy industry reduce its potential
impact on the environment in line with Britain’s target to cut
its greenhouse emissions by 20% by 2010. By 2015 the roadmap
plans to have 20-30% of milk producers trialling new technology
to cut greenhouse gas emissions.
The Inter-governmental Panel on Climate Change (IPCC) calculates
that methane makes up 14.3% of humanity’s contribution to global
warming and data from the National Oceanographic and Atmospheric
Administration (NOAA) in the US shows that atmospheric methane
levels may be rising again after a 10 year period of stability.
A single dairy cow can produce between 550-700L of methane a day
and it has been estimated that methane from cattle in the UK
could account for as much as 3% of the country’s total
greenhouse gas emissions.
Cows’ production of methane is down to the microflora in their
gut that helps them to digest their food. As these microbes
break down the grass’ cellulose, methane is produced as a
by-product, the majority of which is burped up.
David Beever, international nutrition director of Richard Keenan
UK, said: ‘You don’t actually hear the cows burp, but they are
permanently releasing methane.’
Gramina will use sense suppression technology to prevent the
expression of the enzyme O-methyl transferase. Suppressing this
enzyme leads to an increase in the digestibility of the grass
without compromising its structural properties and therefore
less burps and less methane.
Gramina has already tested this modification in temperate
grasses in the lab and glasshouses and is now planning field
trials.
However, some scientists suggest that a cow’s absolute methane
emissions might go up.
Alistair Macrae, a lecturer in farm animal health and production
at the University of Edinburgh, UK, says a diet too rich in
highly digestible carbs can actually increase the amount of
methane a cow belches out. This is because gut microflora
convert more of these sugars into propionic acid, which creates
a more acidic environment resulting in more methane.
Ian Givens, a professor of animal science, at the University of
Reading, UK, says that more digestible forage could push up a
cow’s absolute methane emissions but productivity gains would
mean less methane per unit of milk.
Beever agrees and says, ‘It could increase methane emissions but
it could also increase milk yields, effectively cutting the
amount of methane produce per litre of milk.’
RELATED RELEASE
Bundoora, Victoria, Australia
April 1, 2008
Cows come
home to climate change friendly grass - Australia–NZ partnership
awarded Aus$1.8 M for pasture research
An Australia–New Zealand partnership has won a Aus$1.8 million
grant to develop new pasture grass varieties that are better
adapted to climate change.
The funding will help develop a path to market for new pastures
produced by Gramina Pty.
Ltd., a joint venture of the
Molecular Plant
Breeding Cooperative Research Centre (MPBCRC) and New
Zealand's leading rural services group PGG
Wrightson.
The grant was awarded by the Australia New Zealand Biotechnology
Partnership Fund – a New Zealand Trade and Enterprise initiative
designed to encourage trans-Tasman collaboration in the
biotechnology industry.
‘We’ll be using our technology to help the Australian dairy
industry adapt to future climate changes,’ says MPBCRC CEO Dr
Glenn Tong.
Currently, the dairy farming pasture grass of choice is
perennial ryegrass, a high quality, highly digestible grass that
cows love to eat – and a happy cow is a good milker.
Unfortunately for the dairy industry, perennial ryegrass grows
well only in temperate areas — areas that climate change is
beginning to turn warmer.
And although growing grasses that thrive in hotter climates
climates, so-called warm season grasses, might seem the obvious
solution, they are poorly suited to grazing.
The problem is related to lignin, the stiff wiry component of
plants that supports their structure and makes the plant cell
walls waterproof.
‘Warm season grasses tend to be high in certain kinds of lignin,
making them much less digestible than the temperate varieties,’
says Dr Tong.
‘Low digestibility equals a low energy intake, which drops milk
production. Plus, the longer cows take to digest these grasses,
the more they burp out methane — a major greenhouse gas.’
Dr Tong says that to solve these problems, Gramina will develop
new grass varieties with less of the indigestible type of
lignin. These grasses would increase cows’ energy intake,
leading to higher levels of milk production.
‘You increase the digestibility — you get fewer burps!’
Gramina’s proprietary technologies alter lignin content by
changing the activity of specific genes involved in its
production. Developed by MPBCRC Chief Scientist Prof German
Spangenberg and team, the technology is like a ‘dimmer switch’
for specific types of lignin.
Using warm season grasses will not only lower methane emissions
and increase milk production. These grasses grow faster at the
higher temperatures found in warmer climates.
They are also adapted to higher levels of the greenhouse gas
carbon dioxide, which is predicted to increase substantially
over the next 30 years. Plus, they are also more water
efficient, which is good news for Australia’s drought‑prone
environment.
‘This grant will kick start the process of developing warm
season grasses by modifying the activity of relevant genes, and
will defray some of the substantial commercialisation costs,’ Dr
Tong says.
However, there’s still a long way to go. ‘It takes about $50
million to commercialise such a product,’ he explains. ‘So, this
is only the start of a very long road.’ |
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