Science - September 14, 2017

‘Use more residue streams in animal feed’

The Dutch government can make meat production more sustainable by allowing more waste products from the food industry, such as offal and food remnants, to be used in animal feed. This argument was made by Walter Gerrits, professor holding a personal chair in Animal Nutrition, in his inaugural lecture on 31 August.

© Walter Gerrits

A lot of by-products from the food industry are already used in animal feed in the Netherlands, but there is a ban on the use of offal from abattoirs and food remnants. Bone meal from abattoir waste was banned by the EU in 1999 because of concerns about Creutzfeldt–Jakob disease. The ban on food remnants dates from 1986 and was in response to concerns about the spread of swine fever. This is an extensive residue stream that is mostly converted into bio-energy, says Gerrits. The health risks are tiny when the appropriate processing techniques are used. He believes the government should reconsider these bans so that more by-products can be incorporated into animal feed.

In addition to these policy changes, the Dutch need to eat less meat, argues the Animal Nutrition professor. But from a global perspective, meat consumption will rise in many Asian and African countries. We therefore mainly need to make more efficient use of the available biomass.


Gerrits is working on improving nutrient efficiency — the efficiency with which nutrients are translated into animal growth. In this way he wants to help minimize the amount of land needed to produce animal proteins. Gerrits thinks gains can be made by adjusting the nutrition of animals to better fit their genetic potential. ‘In future, we could also align the supply of nutrients more to an animal’s requirements by recording more information about the animals as they grow.’

But Gerrits also points to developments that could be difficult to square with nutrient efficiency. Take the increased interest in animal welfare. ‘It’s not the pig’s aim to convert as much feed as possible into meat — it’s the pig farmer who wants that.’ For instance, research shows more aggression and tail biting among pigs when their feed contains relatively little protein whereas this feed scores well in terms of protein efficiency and environmental impact. Gerrits is looking at precision nutrition as a way of resolving such conflicts between feed efficiency, the environment and welfare.

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