Research: Managing methane emissions

NSW scientists are working towards reducing methane emissions from livestock by:

1. Increasing productivity

Methane emissions could be reduced by simply reducing the number of cattle. This approach wouldn't help farmers because they need a certain amount of production to make their businesses profitable and Australia's economy would suffer because we export billions of dollars worth of produce each year. Our contribution to global food supply would also drop. So scientists are looking at ways to reduce methane emissions by increasing productivity - if fewer cattle can produce the same amount of milk or meat, emissions will be reduced.

2. Changing diet

Cattle fed by grain produce less methane than cattle fed by pasture. This is because the nutrients required for growth are in a concentrated form in grain, and there is less waste produced in the gut than there would be if grass was eaten instead.¹ So the choice seems obvious: feed them grain … but wait … producing grain creates higher carbon emissions than producing pasture. Why? Because grain is grown, fertilised, has pesticides applied, is processed and then transported. These are all processes which result in greenhouse gas emissions. Scientists therefore have the difficult task of weighing up the advantages and disadvantages of both types of diet.² In addition, in the case of milk-producing cattle, milk quality is negatively affected once grain concentrates exceed more than around 50% of the diet.

3. Genetically improving cattle

Cattle with a greater ability to convert feed into energy will eat less feed and ultimately produce less methane. Scientists would like to be able identify the genes which make some cows more efficient in this way. To then produce a population of cattle which all possess this gene could result in methane emission savings in the order of thousands of tonnes per year. In fact, recent modelling suggests that selection of bulls for this trait within the Australian beef industry will reduce methane emissions by over 550 000 tonnes by 2026.³ You can read more about this project through the Cooperative Research Centre for Beef Genetic Technologies.

Steer fitted with methane collection device. A five litre aluminium collection canister is connected to a point above the nose to collect the air exhaled. The canister is mounted on a plastic saddle held in place by an elastic girth.
Source: Hegarty, R. S., Goopy, J.P., Herd, R.M. & Corkell(2007) Cattle selected for lower residual feed intake have reduced daily methane production. Journal of Animal Science 85:1479-1486. 

The image at right shows the research technique used to estimate the amount of methane emissions per bull. In Armidale NSW, scientists were able to determine that of a group of 76 bulls, 43 were considered to have high feed efficiencies. So compared to the remaining 33 animals, these 43 animals could eat less food for the same weight gains. This research shows that cows bred with high-feed-efficient bulls can produce more feed-efficient offspring so that the farmer doesnt have to pay for as much feed. Because methane production is considered to be related to the amount of food consumed, these findings also provide the potential for less methane emissions from high-feed-efficient animals in the future.

See what students in New Zealand discovered about cow burps - http://www.youtube.com/watch?v=_UepZTrN1Z4

4. Dietary additives

Short-term additives such as dietary oils or lipids (e.g. coconut oil) can be added to reduce methane emissions by decreasing fermentation in the gut and reducing the activity of the micro-organisms in the gut. However, the cost of this strategy, particularly in the case of coconut oil or other medium chain fatty acids (which is what makes these oils highly effective in reducing methanogen numbers in the gut),⁴ is likely to be too expensive for commercial livestock.⁵

While not available yet, research continues into long-term vaccines against rumen micro-organisms that produce excessive methane.

Watch Landline's report about Victorian methane research - http://www.youtube.com/watch?v=G0ebJmJWGPM&feature=channel

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^{1, 2 & 5}Beauchemin , K. A., Kreuzer, M, O'Mara, F. and McAllister, T.A. (2008) Nutritional management for enteric methane abatement: a review Australian journal of experimental agriculture 48:21-27. 

³Alford AR, Hegarty RS, Parnell PF, Cacho OJ, Herd RM & Griffith GR 2006, 'The impact of breeding to reduce residual feed intake on enteric methane emissions from the Australian beef industry', Australian Journal of Experimental Agriculture, vol. 46, pp.81320.

⁴Machmüller A, Soliva CR, Kreuzer M (2003b) Methane-suppressing effect of myristic acid in sheep as affected by dietary calcium and forage proportion. The British Journal of Nutrition 90, 529-540.