Friday, 04 September 2009
sceincealert.com.au
Everybody loves a good fart joke, but the rise in methane emissions is no laughing matter when it comes to global warming.
Now, James Cook University nutritionist Dr Tony Parker thinks he has found a way to decrease this output and he will be testing it on a herd of heifers at the University’s Townsville campus.
Methane is considered more damaging to the ozone layer than Carbon Dioxide and according to researchers, the world’s cattle population accounts for up to 20 per cent of methane emissions from human-related activities.
Dr Parker, from JCU’s School of Veterinary and Biomedical Sciences, and collaborator Professor Rocky de Nys, from JCU’s School of Marine and Tropical Biology, have just received a $7,000 Collaboration Across Boundaries grant to prove their theory that feeding seaweed to cattle will improve their digestion and in turn result in less methane released into the atmosphere.
“Orkney sheep are ruminants that live off seaweed and they do very well on such a diet; so the obvious question is, why can’t cows?” said Dr Parker.
“I like to call it the reef and beef project because it has far reaching implications that come full circle: starting with seaweed, taking in the beef and aquaculture industries, and extending back out to the sea to help conserve the Great Barrier Reef.”
Professor de Nys said that many aquaculture farms used seaweeds and algae to clean their ponds and effluent streams of the waste from fish and crustaceans.
“Effluent water contains nutrients such as nitrogen and phosphorous which are responsible in part for the breakdown of aquatic ecosystems in the Inner Great Barrier Reef,” Professor de Nys said.
“At present, however, there is little incentive provided to farmers to use this bioremediation method as it means they will often be left with a huge biomass that they don’t know what to do with and which has little to no financial value.
“Cattle produce a lot of methane due to their diet. Seaweed, algae and other sea grasses have been proven to be much more digestible than land grass because they have less cellulose and more starch. A better diet for cattle, then, will encourage better digestion and thus lead to a decrease in methane emissions.
“If we can get the beef and aquaculture industries to work together on this we can not only help them reduce their impact on the environment but also improve their profitability,” Professor de Nys said.
The hope is that the incentive to sell their seaweed to beef producers will lead to more aquaculture farmers, and perhaps agricultural farmers, adopting environmentally-friendly algal bioremediation methods to clean their water. By improving the digestion of cattle, growth and milk yield rates will also rise.
Dr Parker said that at least 50 per cent of the global cattle population was located in developing nations, many of which are in the tropics.
“Beef cattle production is the largest animal-based primary industry in the tropics,” Dr Parker said.
“The quality of the pasture often deteriorates in the winter compromising animal growth and increasing methane emissions. If seaweed can improve on that and at the same time contribute to a reduction in global warming then we’re going to give it a go.”
Two species of ‘green tide algae’ (Cladophora coelothrix and Chaetomorpha indicia), identified as the best for bioremediation of pond effluence due to their hardiness, fast growth and efficient nutrient uptake, will be used for the experiment.
A herd of tropically-adapted Bos indicus heifers will be split into six groups and, over 28 days, fed a basal diet of tropical forage hay. Each group will have an increased inclusion of dried green tide algae added to their feed to establish the amount of seagrass that can be tolerated by the cows to maintain a healthy, productive weight and milk yield.
Dr Parker will also have the unenviable task of measuring at what quantity the seaweed is most effective in terms of reducing methane emissions.
“I’m not looking forward to that part of the process,” he admitted.
