‘Why cows can be even more of a grass act’
Dr Joan Edwards is a research scientist at Aberystwyth University.
Dr Joan Edwards investigates how the grass that ruminants consume can increase their productivity while reducing their environmental impact
THERE is no denying that ruminants produce significant amounts of methane, a potent greenhouse gas.
However, the flip side of this is that they do so as a by-product of a process which allows them to utilise plant material that we cannot.
This unique attribute means that ruminants play a vital role in terms of providing enough safe and nutritious food to feed the world’s growing human population.
Ruminants do this by enabling 68% of the world’s agricultural land, managed as natural or improved pasture, to be used for food production.
The basis of this unique attribute is their three extra stomachs; the largest (80-100 L in a mature cow) and most important of which is the rumen.
The rumen is home to billions of microbes, which break down and use the consumed plant material that the ruminant itself (like us) cannot.
This results in the formation of energy, protein and other products which the ruminant can then utilise, enabling meat and milk production.
However, due to the fact that rumen microbial processes occur in the absence of oxygen (O), excess hydrogen is not expelled in the form of water (H²O) like in our respiration – but instead burped out as methane (CH4).
Research at Aberystwyth University has shown that the type of plant material consumed by grazing ruminants influences the microbes in the rumen, and the amount of methane that ruminants produce.
As a farmer’s daughter I can appreciate that a ‘green’ plant-based approach to reducing the environmental impact of sheep and cattle farming, whilst increasing productivity (as methane represents a loss of energy as well as a greenhouse gas emission), is both a manageable and cost-effective answer for Welsh farmers.
Sheep and cattle farming are crucial to our nation’s economy, representing 75% of our agricultural production.
My research focuses on how plant activity, as well as composition, can be used to further optimise this approach.
Believe it or not, at least half the plant material eaten by grazing ruminants is still alive for up to six hours in the rumen – during which time it can greatly change the nutrients available to rumen microbes.
This is due to the fact that the plant uses everything in its arsenal in order to try and survive – it doesn’t know its fate is already sealed.
Recent findings, enabled by new sequencing technologies, have allowed us to advance our understanding of the way the eaten plant reacts to the rumen environment, as well as the rumen microbes.
Research is now underway to determine how these reactions can be optimised to enable more efficient provision of plant nutrients to rumen microbes.
In the future, this will enable the best use of our nation’s grassland for food production, with minimal environmental impact.
To contact Joan please email jae@aberystwyth.ac.uk
This article first appeared in the Western Mail‘s Health Wales supplement on 14th January 2013, as part of the Welsh Crucible series of research profiles.