Cutting dairy's methane emissions also good for efficiency

Monday, April 2, 2012

It's estimated that livestock farming produces 18 per cent of the world's greenhouse gas emissions. Now, the Netherlands is showing that higher quality feed and efficient cow management can dramatically improve the situation

by NORMAN DUNN

It's called the "battle of the burp" by the press here in Europe and it's being fought on research dairy farms throughout the world just now.

The goal is to drastically reduce the two billion metric tons of CO² equivalents produced every year by cattle. Of course, there are still arguments as to whether greenhouse gas output is actually to blame for climate warming. But the new Global Research Alliance (GRA), a scientific team from 36 countries, hasn't been created to debate that question. The GRA exists to look into the various influences on greenhouse gas production and has recognized right from the start that, where cows (and other livestock) are efficiently managed and fed, less of these gases will be produced.

Thus, what GRA scientists, such as Dr. Jac Meijs from the Livestock Research Institute in the Netherlands's Wageningen University, are really doing is establishing blueprints for increasing farming efficiency.

Dr. Meijs explains that half of cow gas production is burped out as methane. Of the remainder, 30 per cent is nitrous oxide (from manure mainly) and the final 20 per cent carbon dioxide, partly from the production of fertilizer for grassland. Methane has over 20 times the climate-damaging potential of CO² and nitrous oxide 300 times. The result?  Livestock farming the world over is now producing around 18 per cent of all human-activity greenhouse gases, or 4.6 billion metric tons per year.

In fact, the Dutch achieved a 20 per cent reduction in greenhouse emissions from their livestock farms from 1990 to 2008 and another 10 per cent is expected by 2020. There are literally dozens of GRA-linked scientific projects with similar targets all over the world now. How to reduce methane output from cows is one of the major programs. After all, a single cow burps up 20 grams of methane from every kilogram of feed it consumes.

The Dutch researchers scored their first victories out in the field and in the feed bunker. Young grass, for instance, proved to produce 15 per cent less methane from the rumen than older grass. This means intensive grazing systems still offer an overall reduction in greenhouse gases from cattle, even if these require more nitrogen fertilizer which, in turn, increases production of nitrous oxide in the atmosphere.

Corn silage is even better at cutting methane production. Oilseeds in the dairy cow diet are especially efficient in this respect, although there's obviously a limit to the proportion of sunflower, rapeseed or linseed in the trough before digestion is impaired. But feed expert Prof. Jan Dijkstra of Wageningen University's Animal Nutrition Group reckons fine-tuning all these factors has the potential of halving cow methane production.

But, while Europe and North America are well on their way to achieving important savings in greenhouse gas emissions from cattle, the really important campaigns are now taking place within the vast ruminant populations of Third World countries.

Away from the large commercial farms in Africa and the Far East, the feed offered the average cow is generally of fairly low quality. Research underlines that poor feed means higher rates of methane production, while increasing its quality brings better output and more income for the farmers.

"Improving income levels of farmers and achieving a drastic reduction in emissions can go hand in hand," explains the Wageningen University report on the work so far.  

The Dutch record backs this claim to the hilt. Consistent improvements in dairy cow efficiency over the past 40 years in this country have not only doubled average yield per cow, they've halved methane production per cow, too.  

The key factors in this success are now being implemented in the less-developed cattle regions of the world. Better managed grazing and silage-making is one approach. Improved calf care is needed, too. This means more replacement heifers surviving to join the herd, so that older and less efficient milk producers can be culled.

Whatever the outcome of the greenhouse gases and climate change argument, the GRA results show that the research side-effects can bring real increases in milk (and beef) production efficiency where they're really needed. And maybe that's the most important result of all. BF

Norman Dunn writes about European agriculture from Germany.