An Italian case study shows promising results for adding bakery by-products as a feed ingredient to lactating cows’ diet. 

Italy has a high dependency on cereal import from no EU countries. It 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.

Bakery by-products, former food that are no longer useful for human nutrition, may be part of the solution. 

“Compared to corn meal, bakery by-products are characterized by a lower starch content, which is more digestible following cooking, and it has a higher content of lipids and sugars. They can thus replace corn meal as an energy source in the ration,” says Associate Professor Stefania Colombini at the University of Milan.

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

Colombini and her colleagues have evaluated case studies on different cattle farms that use some sources of by-products in their diet. 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 in their diets as energy source.

The researchers concluded that the circular diet were more sustainable, in terms of global warming potential (GWP) related to milk production. The milk production pr cow was also slightly higher. They calculated the impact both per kilogram fat and protein corrected milk and per individual daily diet, using Life Cycle Assessment approach (LCA).  

“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 explains that the difference in nutrient profile has important consequences for cattle feeding, offering several advantages over traditional corn meal. The rapid fermentation of corn starch, can cause the dangerous ruminal pH-drop, known as ruminal acidosis. On the other side, the lower more digestible starch, along with higher simple sugar and fats, tends to release energy more gradually. This promotes a more stable rumen environment and better digestion of fibre.  

“The higher levels of lipid and sugars significantly increase the feed’s energy density. This is particularly advantageous for high-producing dairy cows or growing beef cattle that have very high energy requirements. Many bakery by-products are naturally rich in fats and sugars, which makes them highly palatable for cows,” says Columbini.

Rumination trials indicate higher rumination activity

Rumination trials showed increased rumination time activity when cows were fed with the bakery-by products diet. Higher rumination activity usually promotes higher digestibility, especially with regards to fibre fraction, which in turn lowers GHG-emissions. The results of the trial also showed a tendency for an increase in fibre digestibility of cows fed the bakery by-products diet.

“Automatic measures of cows chewing activity shows higher chewing activity. The studies confirm that higher digestibility lowered the cows’ enteric methane intensity (g/kg milk), because of enhanced ruminal fermentation”, says Colombini. 

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. 

“The use of bakery by-products as animal feed offers high potential for global upscaling, especially in Europe, as a circular economy solution. However, large-scale adoption is constrained by the need to develop efficient, widespread collection logistics and maintain consistent nutritional quality. This practice would position Italy and Europe as leaders in reducing dependency on imported energy feed ingredients which is becoming a critical issue too,” Columbini concludes.