Effective and sustainable production systems within aquaculture and agriculture

Milk on grass and by-products

SLU 120402 7935 jsg

Photo: SLU

Arable land is needed for growing cereals, protein crops and energy production. According to current estimates, including those by the FAO, global demand for food will increase by around 70% by 2050. The associated increase in demand for agricultural land may require changes in how farm animals are fed.

Cattle are capable of converting forage (grass and clover) to high quality protein in the form of milk and meat. Sweden has good pre-conditions for efficient production of forage. In the past 50 years, the diet of dairy cows has consisted of 50% cereals. The researchers in this project are seeking to create feeding systems for dairy cows based solely on forage and by-products from food and bioenergy production. These systems need to be both competitive and appropriate from a long-term environmental perspective. In order to complement the nutrient content of the by-products, within the framework of the project they are being combined with forage of particularly suitable composition. The by-products under investigation are:

  • Sugar beet pulp
  • Rapeseed cake from rapeseed oil production
  • Glycerol from biodiesel production
  • Distiller’s grain from ethanol production

Some of these by-products are already used in feeds for dairy cows, but the unique aspect of this project is that diets containing absolutely no cereal grain or soya are being tested.  

Mjolk pa bi produkter

Photo: SLU

“We will probably continue to need cereals in the future, for example it is good to have them in the crop rotation, but in this project we wanted to test an exclusive  system” (research leader Kjell Holtenius)

In order to create a good diet based on these by-products, it is important to find a forage that does not have too high a protein content. The researchers are investigating how different fertilisation and harvesting times affect the protein content. They are also conducting variety trials on modern varieties. Access to by-products differs in different parts of the world and the diets will be optimised according to local conditions. 
The project is studying how different feedstuffs affect milk yield and animal health and the environmental effects of different feeding strategies. The economic value of the feeds will also be assessed. The hypothesis is that milk production will probably decrease somewhat, but that feed costs will also decrease.


Name: Kjell Holtenius, SLU Uppsala
Email: This email address is being protected from spambots. You need JavaScript enabled to view it.
Funding: SEK 14,9 million
Project period: - december 2018
Find out more about Kjell

Project pages



3 loggor ihop CMYK 171211 02