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By-products from the generation of bioenergy have potential as cattle feed

Dairy cows can utilise by-products from the growing bioenergy production. This is the conclusion of a report from DCA that has gathered available knowledge and experience in the area of using these by-products as a feed component for dairy cows.

[Translate to English:] Biprodukter fra produktionen af bioenergi kan i høj grad udnyttes i fodringen af malkekøer uden at det har negative konsekvenser på parametre som foderoptagelse eller mælkeydelse og -kvalitet. Det er konklusionen af en rapport fra DCA.

By-products from the production of bioenergy can be widely used for the feeding of dairy cows without any adverse effects on parameters such as feed intake or milk yield and quality. This is the conclusion of a report from DCA.


The rapidly increasing production of bioenergy at global level offers new interesting opportunities for cattle farming to make use of by-products that result from the steadily increasing bioenergy production.


In a new report from DCA – Danish Centre for Food and Agriculture, scientists from Aarhus University together with DLG, Arla Foods and AgroTech have analysed the experience and knowledge of the suitability of the by-products as part of the feed ration for dairy cows.


And the conclusion of the report is clear: By-products from the production of bioenergy can be widely used for the feeding of dairy cows without any negative effects on parameters such as feed intake or milk yield and quality.


The byproducts from the bioenergy sector are first and foremost dried distiller’s grain, glycerol and protein-rich feed cake and meal, such as rapeseed cake and meal.


Byproducts can substitute soy

Distiller’s grain, which is a by-product of the manufacture of bioethanol from mainly wheat and maize, comes in different forms. Distiller’s grain has, however, not been widely used in Denmark, but the product can form part of the feed ration.


- There is good evidence that both the fresh but especially the dried form of a good and known quality of distiller’s grain may constitute up to 30 percent of the ration (on a dry matter basis) for dairy cows and substitute good quality protein sources such as soy and canola products without any negative effects on feed intake or milk yield, explains Jakob Sehested, associate professor in the Department of Animal Science at Aarhus University.


The by-products from biodiesel production are the aforementioned glycerol and protein-rich feed cakes and feed meal. Although glycerol is a novelty as an animal feed commodity, the authors behind the report believe that crude glycerol of a good quality can form a significant part of the diet of dairy cows and replace starchy energy feed sources. The same is true of rapeseed cake and meal, which can also be used with good results in the feeding of cows and can replace soybean meal.


Low carbon footprint

The carbon footprint of the by-products – where emissions from cultivation, processing and transport are the largest sources – is also favourable compared with soy, not least because of the large emission factor related to the shipping of soy from South America to Europe. Where soy, according to the report, has a carbon footprint of 725 g CO2-equivalents, distiller’s grain has a footprint of just 300 g.


Jakob Sehested points out that the effect of the by-products on milk composition and quality is an area that current has a lot of attention. If the by-products change the fat content and fatty acid profile of the ration, this will affect the fat content and fatty acid profile of the milk. While feeding distiller’s grain is not expected to affect the taste of the milk, aberrations in milk flavour have been detected in a few instances when large quantities of glycerol (15 percent of dry matter) and rapeseed cake (20 percent of dry matter) have been included in the feed ration.


The report (On available in Danish - Biprodukter fra produktion af bioenergi som fodermidler til malkekøer) is a result of the project "Improving the quality of by-products as feed ingredients for dairy cows", which runs from 2012 to 2014 and is funded by the Milk Levy Foundation, AgroTech, DLG, Arla Foods and Aarhus University.


Contact: Associate Professor Jakob Sehested, Department of Animal Science, telephone: +45 87157893, email: jakob.sehested@agrsci.dk


Fact box:


Examples of products


Distiller’s grain is an umbrella term for the residual fraction remaining when the starch content of wheat or maize has been fermented and the ethanol distilled out.


C5 molasses is a treacly residual of the production of ethanol from straw.


Rapeseed cake is the residual fraction from the cold-press of rapeseed for the production of rapeseed oil. This may also be done with the additional use of heat.


Rapeseed meal is the residual fraction when oil has been chemically extracted from rapeseed with an organic solvent.