ENVIRONMENT ▶▶▶
Promising efforts to lower enteric methane
Researchers around the world are searching for new ways to lower emissions. Projects in Denmark and Canada have assessed emissions-lowering measures, and Swiss feed additive company DSM Nutritional Products has developed a new active ingredient that shows great promise.
BY MELANIE EPP
Danish research In Denmark, a new project aims to reduce methane emissions via feed and is investigating the biological reasons that cows differ in methane production. Peter Lund, Professor of Sus- tainable Dairy Production in the Department of Animal Sciences at Aarhus University, is leading the project. The project will measure methane production, for instance, in cows that are fed the same diet but at different lactation points to see if there are differences. “If we have these two animals in front of us and one responds a lot and is generally low in methane, what is the reason?” says Lund. “Is it because the rumen microbial community differs? Is it because the animal chews the feed in a different way? Is it because it produces more saliva? That the pH in the rumen dif- fers? Is it because of the rumen size? We don’t really know.” Knowing how cows respond will help determine which cows will best respond to certain mitigation strategies, says Lund. Furthermore, he believes breeders could then use this infor- mation to include lowered methane production in their breeding goals. The four-year project is in its second year. It is part of a num- ber of projects all aimed at more climate-friendly dairy pro- duction. The research is a collaborative effort between Aarhus
Enteric methane
Nearly 60% of dairy greenhouse gas emissions come from enteric methane, which is produced in the cow’s rumen during digestion. Enteric methane emissions from dairy production contribute an estimated 1.7% of total global greenhouse gas emissions.
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University, the University of Copenhagen, a few private companies, including DSM Nutritional Products, and SEGES.
Canadian research In Canada, research led by Dr Karen Beauchemin, a livestock specialist at Agriculture and Agri-Food Canada, is being used to develop methane mitigation strategies to help the coun- try’s dairy sector reduce its impact on the environment. Like the researchers in Denmark, the Canadian team noted differences in methane production from one cow to another. A high-producing cow averaging 10,250kg of milk per lacta- tion, for example, produces approximately 375g d-1 of meth- ane, while a low-producing cow averaging 500kg of milk pro- duces about 180g d-1 of methane. This loss in methane energy typically represents 5.7–6.5% of total gross energy in- take, depending on diet composition and milk production of the cow. The scientists believe that improved understanding of the process of methanogenesis combined with further un- derstanding of how the animal and its diet, feed additives, and management factors impact methanogenesis could lead to development of better methane mitigation strategies. Improving feeding strategies seems to show the most prom- ise. For instance, it was found that increasing dietary fat in feed reduces energy lost as methane by up to 20%. Tested feed includes crushed oilseeds – such as sunflower seed, canola seed and flaxseed – and dried corn distillers grain. Similar reductions were found when whole cottonseed, plant oils and some ethanol by-products were added to the diet. Overall, each percentage point of crude fat added to dietary dry matter reduced methane production by five percentage points, says Beauchemin. While there’s some room to add fat to the diet, she is careful to note that too much fat can impact cattle health and increase production costs. Beauchemin’s team is also investigating feed additives, in- cluding plant extracts (condensed tannins, saponins and es- sential oil products) and rumen modifiers such as yeast, bac- terial direct-fed microbials and enzymes. While essential oils derived from garlic, thyme, eucalyptus, oregano, cinnamon and rhubarb have been shown to decrease methane produc- tion in vitro, Beauchemin says there are few controlled re- search studies that have examined their anti-methanogenic effects. Furthermore, there is some concern that some of the oils may create an off flavour in milk. Further studies are
PHOTO: RONALD HISSINK
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