Cows eating left-overs from bakery products may produce more sustainable milk

An Italian case study shows promising results for adding bakery by-products as a feed ingredient to lactating cows’ diet. Preliminary results indicate that this may increase milk production and lower global warming potential on farm level. 

In Italy, dairy farms experience severe crisis due to economic speculation and climate change. This is challenging the sustainability of milk production. 

“In particular, rising raw material prices, drought and the presence of mycotoxins in maize have prompted dairy farms to make changes in the feed ration composition of lactating cows”, says researcher Martina Pavesi, Research Fellow at the University of Milan in Italy.

akery by-products may lower global warming potential from milk production 

At the moment, Associate Professor Stefania Colombini and colleagues at the University of Milan, are evaluating case studies on different cattle farms that use some sources of by-products in their diet. So far, the most promising result was seen in a farm that changed from a standard diet to a circular one, including bakery by-products. The cows in this case study farm were fed bakery by-products (former food) in their diets as energy source. The researchers concluded that the circular diet seemed to be more sustainable, in terms of global warming potential (GWP) related to milk production. They calculated the impact both per kilogram fat and protein corrected milk and per individual daily diet, using Life Cycle Assessment approach (LCA). 

The same farm recently changed from milking parlor to automatic milking system. This will be considered and modelled into research calculations, but the researchers still believe that the bakery by-product diet has a positive outcome in terms of sustainability. 

“In Vivo trials where cows were fed a control diet or a bakery by-product diet support the findings from the case farm. The milk production of the cows who were fed bakery by-products was a little higher” says Colombini. 

She adds that they expect a positive effect on feed-food competition, since bakery by-product from bakeries and supermarkets are not useful anymore for human nutrition.

Rumination trials indicate higher rumination activity

These days the researchers are conducting rumination trials. So far it seems like rumination time activity is increased by the bakery-by products diet. 

“Automatic measures of cows chewing activity shows higher chewing activity. We are currently waiting for digestibility data to verify if the higher rumination activity also promotes higher digestibility, especially with regards to fibre fraction”, says Colombini. 

Higher digestibility will usually lower the cows’ enteric methane intensity (g/kg milk) as a result of ennached ruminal fermentation. 

Questions are raised about the access to bakery by-products in large scale, but the results so far are promising for looking at other by-products included in diets to dairy cows. 

Dialogue with farmers and case studies from other countries

Dialogue and knowledge sharing are an important part of the CircAgric-GHG project. At the beginning of January 2024, the Italian researchers will arrange workshops with private companies and farmers to explore opportunities and barriers to adopting circular practices in Italy. Case study farms will receive individual feedback on their LCA-score and get advises of how they can lower the GWP level from their farms.  

Research colleagues in the project will further explore circular practices in other countries, such as lamb production in Spain and potato production in Norway. One on CircAgric-GHG goals is to share knowledge about circular practices on and between farms, regionally, nationally and internationally. 

Master student Ruben Carminati is sieving the ration and leftovers, preparing diet for the cows with bakery by-products at the University of Milan “Angelo Menozzi” Experimental farm.
Master student Ruben Carminati is sieving the ration and leftovers, preparing diet for the cows with bakery by-products at the University of Milan “Angelo Menozzi” Experimental farm.
Bakery by-product used in trial.
Adding bakery by-products as a feed ingredient to lactating cows’ diet may increase milk production and lower global warming potential on farm level.
Weight is measured using a hypsometer to observe any changes in weight throughout the trial.
The researchers collect samples of diets, leftovers, and individual ingredients from the feeding lane. These samples are then subjected to chemical analysis in the lab and digestibility tests. Additionally, feces and urine are also collected.
Each time the cows are milked by the robot, milk samples are collected. The quality of the milk is then analyzed to observe changes, for instance in protein or lactose levels, which might occur due to changes in their diet.

Other relevant studies:

A. Kaltenegger, E. Humer, A. Stauder, and Q. Zebeli (2020) Feeding of bakery by-products in the replacement of grains enhanced milk performance, modulated blood metabolic profile, and lowered the risk of rumen acidosis in dairy cows. J. Dairy Sci. 103:10122–10135 

A. Kaltenegger, E. Humer, C. Pacífico, and Q. Zebeli (2021) Feeding dairy cows bakery by-products enhanced nutrient digestibility, but affected fecal microbial composition and pH in a dose-dependent manner. J. Dairy Sci. 104:7781–7793 

Khiaosa-ard R, Kaltenegger A, Humer E and Zebeli Q (2022). Effect of inclusion of bakery by-products in the dairy cow’s diet on milk fatty acid composition. Journal of Dairy Research 89, 236–242. 

By: Anette Tjomsland Spilling. 
Photos: University of Milan. 
Published: 10.01.24

Two workshops with Norwegian farmers about circular agriculture

Circular agriculture involves strategies for better utilization of resources and nutrients, reduced use of external inputs, and replacing fossil energy with renewable energy. What do farmers perceive as barriers, possibilities, and solutions to circular agriculture? 

The CircAgric-project conducted two workshops with farmers in Norway in October and November (2023). The farmers were prompted with questions about how to enhance circular agriculture, on-farm, and between farms. 

The primary findings were:

– A healthy farm economy is esseintial to introducing new circular practices.

– The farmers want to find the best solutions tailored to their own farm.

– It is important to recognize the farmers knowledge and efforts.

– There is a demand for more holistic policy instruments and support.

– It is necessary to recognize dilemmas between conflicting climate and environmental considerations.

One workshop took place at NIBIOs research station Tjøtta, located at Helgeland coast, between Trondheim and Bodø. The agricultural systems here are predominatly grassland and pasture-based livestock production.

“Key measures emphasized by the farmers were reduced use of external inputs such as fertilizers and feed, improved grass yields, and cultivation of clover to fix nitrogen. One farmer highlighted seaweed as an important alternative to feed and fertilizer on Helgeland”, says Vibeke Lind, Research Scientist at NIBIO Tjøtta, and Project Leader of CircAgric-GHG.

The other workshop was organized in Nord-Østerdalen, a region in the interior of Southern Norway, primarily mountainous, with a subarctic continental climate. Agriculture is vital for employment in the region and dominated by gras production and ruminants. Outfields are used for grazing, and the regions are one of the two core areas for summer dairy farming in Norway.

The farmers emphasized more and better roughage, composting and the importance of forest and own logging, which differed from the focus of the coastal farmers at Helgeland, says Valborg Kvakkestad, Research Scientist in NIBIO, with the responsibility for task 4.3 in the project. She also lives in a farm in a neighbouring municipality.


By: Anette Tjomsland Spilling
Photos: Vibeke Lind and Liv Jorunn Hind/NIBIO
Published : 05.01.24

Summary of UK workshops with industry, policy representatives, and farmers

Dialogue with stakeholders is an important part of the CircAgric-GHG project. Project partner Bangor University have arranged two online workshops with industry and policy representatives, and interviews (online and on-farm) with farmers. Opportunities and barriers to adopting circular practices in UK agriculture were explored, and key factors influencing farmers’ decision-making towards adoption were revealed. Stakeholders shared a positive perception and clear understanding of the concept of circularity, but awareness of the term was lacking. Targeted and trusted advisory support was desired by farmers, whilst they saw incentivisation through future government payment schemes as a key enabler. Regulation was perceived as a major barrier, such as limits on the quantity and timing of manure application, planning permission for renewable energy projects, and use of alternative feed ingredients (e.g., food waste streams). Nevertheless, positive reframing of government policy to include circularity as a major net zero strategy, whilst raising awareness and communicating the benefits of circular practices, will likely enhance its adoption. PhD Researcher Ffion Evans made this figure to summarize the findings.

Read more about the UK workshops in this brief research summary report. 

Mid-term project meeting in Galway, Ireland, 4-7.9.2023

CircAgric held our mid-term project meeting in Galway, Ireland. During the meeting, we visited a dairy farm that is part of the project to James Humphreys, Teagasc. James is following 20+ farms to introduce and include circular practices. The farm we visited has very few inputs and focus more on milk solids than milk yield in litres per cow. The around 300 cows are grazing all year round on pastures with high inclusion of clover.  

Photos: Vibeke Lind, David Styles and James Gibbons.

Measurements of methane and CO2 from the barn at NIBIO Tjøtta

In CircAgric-GHG, researchers use drones with advanced measurement equipment to try to estimate greenhouse gas emissions from various sources on the ground. In August 2023, Norbert Pirk and Alouette van Hove from the University of Oslo(UiO) visited NIBIO Tjøtta. They used drones that measure methane and CO2 respectively at a height of about 20 metres above the barn, which houses between 60-70 cows. In addition, wind strength and wind direction were measured by suspending equipment in a so-called flux tower near the barn. If, for example, it is very windy, this must be calculated in, as the uncertainty in the measurements becomes greater. The measurements from the air can be compared with measurements of individual emissions from the cows inside the barn. This makes it possible to check whether the measurements in the air appear to be correct. This is groundbreaking work, and the big question is whether it is possible to measure emissions in this way, or whether it is still necessary to measure at the individual level. The researchers from UiO will also test the method in Germany, and hopefully in Kenya.

Photos: Vibeke Lind/project team

Circular Agriculture to improve sustainable food production

Circular agriculture aims to reduce external inputs to farms whilst maintaining production and profit. In the past mixed crop livestock farming, a system that grows crops and raise livestock on the same farm, was common. However, driven by economy competitiveness and agricultural policy, production has become more specialized and less connected. This video summarize how circular agriculture can improve sustainable productions compared to more intensive farming systems.

Video: Ffion Evans

Drones that will be used to measure climate gas emissions from ruminants

Norbert Pirk, researcher at Universitetet i Oslo (UiO), demonstrates which drones they have available and plan to use in CircAgric-GHG. The project will use various remote sensing technologies to detect CH4 and CO2 fluxes from landscapes and animals.

Video: Anette Tjomsland Spilling

Kick off meeting in Garmisch-Partenkirchen, Germany, 10-12.05.22

Photos: Vibeke Lind and Clemens Scheer

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Forskere fra åtte land skal undersøke hva europeiske og afrikanske bønder kan lære av hverandre. Prosjektet CircAgric-GHG skal gi økt kunnskap om resirkulering og smart ressursbruk, samt metoder for å redusere klimagassutslipp fra gårder og beite.


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