In order to provide enough milk to ensure a steady supply of butter, cheese and ice cream, dairy cows in Norway and other countries are dependent on imported protein sources in their feed.
For ten weeks this winter, Foods of Norway’s researchers have been testing a novel diet in dairy cows. In the test diet, soy was replaced by yeast – a microbial protein source that can be produced locally from spruce trees and seaweeds.
The aim of this feeding trial is to prove that product quality and animal health is unaffected when soy is replaced by yeast in the feed.
– Never before has the effect of yeast on milk quality been analysed so thoroughly, says PhD-student Martine Olsen, who´s studying the effect of novel feeds on milk quality in the centre.
Yeast - a protein bomb
Foods of Norway aims to reduce Norway’s reliance on imported feedstuffs and to lower the environmental footprint of food production. The development of novel, sustainable and local feed ingredients, such as yeast, is thus a crucial task.
Yeast is a type of fungi with a protein content of 50-60 per cent – even higher than the imported soybean meal that is currently the most important protein source in compound feed for farm animals like cows and pigs.
During the feeding trial with dairy cows, one group of cows was fed a diet where the soy bean meal was replaced with yeast, while another group was fed a standard compound feed with soy and a third group was fed a low-protein diet with barley instead of soy.
Preliminary results show that the cows liked the yeast-based feed and their milk yield was similar to that of the animals fed the soy diet.
12,000 litres of milk
From 12,000 litres of milk, Foods of Norway`s researchers have made 420 kilos of cheese, 300 litres of ice cream and 30 kilos of butter in the pilot dairy plant at NMBU. Taste, coagulation properties and protein content are among the many parameters measured when the products are analysed.
– For yeast feed to become a viable alternative to soybean meal in diets for dairy cows, the quality of the dairy products has to be just as good or better, says PhD-student Olsen.
The first results on product quality are expected by the end of this year.
– Our samples are currently being analysed, and then this data needs statistical analyses. Also, the butter needs to be stored and the cheese needs to be ripened, explains Siv Skeie, professor at NMBU and responsible for product quality in Foods of Norway.
A sustainable feed resource
Yeast is a sustainable feed resource. It has a rapid growth rate and its production doesn´t require any agricultural land, uses little fresh water, is unaffected by changing climatic conditions and can be produced from non-food biomass like trees and seaweeds. This is done by using special enzyme technology to convert these biomasses into sugars that are needed in the fermentation of yeast.
Yeast feed will never be able to compete with the cost of soy. Documenting value-added effects of yeast on animal health and sustainability is thus an important research task in Foods of Norway.
– Yeast as an alternative to soy in animal feed could increase sustainability in food production and improve Norway´s self-sufficiency. This will benefit Norwegian farmers – and in the end, Norwegian consumers. It should be possible to build an industry on yeast production in Norway, says Professor Skeie.
TINE: – Promising
Several of Foods of Norway´s industrial partners have contributed to this value chain from tree biomass to the final dairy products. Felleskjøpet and TINE have been heavily involved in the planning of the experiment, and the yeast production process was undertaken in collaboration with Borregaard. Lallemand produced the yeast for the trial, Felleskjøpet composed the yeast diet and the analyses of milk and cheese are performed in close cooperation with TINE.
– We are currently investigating the effect of yeast on the chemical composition of the milk, i.e. fat, fatty acids and protein content. We are also looking at sensory quality, durability and coagulation properties, says R&D Director in TINE, Eirik Selmer-Olsen.
There are approximately 220.000 dairy cows in Norway (2019). One dairy cow consumes 8,5 kilos of compound feed per day and some 2600 kilos per year, according to TINE - Norway's largest producer, distributor and exporter of dairy products.
– In accordance with national goals, TINE aims to increase the proportion of local ingredients in compound feed for farm animals. Co-products from forestry are an abundant resource in our country. The development of yeast derived from tree biomass is promising as a novel protein source in feed, says Selmer-Olsen.
– Gives us valuable experience
Due to practical challenges involved in producing enough sugar solution from woody biomass in time, the batch of yeast used in this dairy-cow trial was produced from sugars from molasses.
However, the chemical and nutritional composition of the yeast was the same as for yeast fermented on sugar solutions from trees, explains researcher Liv Torunn Mydland, who`s in charge of Foods of Norway’s research on the impact of novel and improved feed ingredients on nutritional value and feed efficiency.
– This feeding trial with dairy cows will thus give us valuable experience on how we can use yeast from Norwegian spruce trees in dairy cow rations in the years to come, says Mydland.