CHINESE PhD candidate at The University of Western Australia (UWA), Xixi Li, is taking a tar bush to the touchy subject of reducing controversial agricultural green house gas emissions.
With two thirds of Australia’s agricultural emissions coming from enteric methane produced during rumen fermentation in ruminants such as sheep, it was high time feed manipulation was investigated to lower the level of what accounts for about 10 per cent of national emissions.
To further pursue her PhD research on how the Australian native plant, Eremophila glabra, or tar bush, when consumed by sheep, reduces methane production in the rumen, she is one of two recipients of the 2011 Mike Carroll Travelling Fellowship. The other is fellow UWA PhD student, Chelsea Fancote.
Ms Li and Ms Fancote this month attended the 8th International Symposium on the Nutrition of Herbivores in Wales, UK, where Ms Li presented a paper and discussed her UWA Institute of Agriculture (IOA) research with world leading scientists in the field of livestock production.
According to her PhD Supervisor, UWA IOA Animal Production Systems Program Leader, Professor Phil Vercoe, her ultimate aim is to develop more diverse forage bases for grazing ruminants in Australia, including plants such as E. glabra.
“Xixi has already demonstrated that tar bush has dose related, persistent, modulating effects on rumen microbes and she will use this exciting finding to design an experiment where she will feed tar bush to sheep in respiration chambers to accurately measure methane emissions and also to ensure the effects she’s observed in the laboratory are replicated in the animal itself,” he said.
Professor Vercoe, in a glowing Mike Carroll Travelling Fellowship reference for Ms Li to UWA IOA Director, Winthrop Professor Kadambot Siddique, described her as intelligent, self motivated, organised and one of the most dedicated students he’d ever supervised.
“She is clearly going to make a significant contribution to science and has already established close and valuable collaborations between UWA and CSIRO during her PhD project.”
After screening more than 100 native plants as feed supplements to improve feed intake, digestibility and rumen fermentation, Ms Li and her colleagues selected E. glabra, a shrub that tolerated harsh growing conditions and could provide livestock fodder in WA, even in drought.
“I have found an optimal inclusion level of E. glabra, which can reduce methane production by about one third, while not adversely affecting general rumen fermentation,” she explained.
“It seems that with no effect on total volatile fatty acid concentrations, the major end products of rumen microbial fermentation, E. glabra alters the diversity and activity of ruminal microbes.”
Ms Li believed that if methane production could be reduced, while increasing total volatile fatty acid production, animal production could be improved. However, she stressed that E. glabra only needed to make up a part of the animal’s diet to have these effects and its value would be as a component of a more diverse mixture of plants for grazing.
“This would give us a solid base to reduce greenhouse gas emissions from ruminants and contribute to developing green, sustainable and profitable grazing systems for WA sheep.”
The Mike Carroll Travelling Fellowship, a memorial to the late Dr Mike Carroll, former Director General of the WA Department of Agriculture, recognises his devotion to agriculture and selfless efforts to improve the lot of farmers, the wider agricultural community and scientific colleagues.
Dr Carroll’s wife, Helen, said Fellowship recipients were chosen on their academic abilities, relevance of studies to an important area of Australian broadacre agriculture, their potential to benefit from the experience and their enthusiasm to impart the findings of their travels to the scientific, farming and wider community on their return to WA.
