Reducing Food Waste: Concentrates with ‘Former Food Products’ for Dairy Cattle

Feeding food no longer suitable for human consumption (‘former food products’ or FFPs) to dairy cattle is a promising approach for reducing food waste. When included in dairy diets, FFPs do not affect the cow’s metabolism, but do not reduce methane production either. 

Feeding ruminants with resources that are unsuitable for humans, such as grass and ‘former food products’ (FFPs), helps to reduce feed-food competition. In addition, growing concern about food security is prompting research into alternatives to cereal grains as concentrates for livestock, such as food industry by-products. Despite this, the effects of FFPs on animals, and specifically on ruminants, have scarcely been investigated to date.

Studying the effect of replacing cereal grains by ‘former food products’ and cocoa bean shells

Agroscope studied how replacing cereal grains in concentrates with FFPs (leftovers from the bakery industry) – with or without the addition of cocoa bean shells (CBS) – affects ruminal fermentation, methane production and blood metabolites in early-lactating dairy cows on a grass-based basal diet. The addition of cocoa bean shells was tested in terms of the potential methane-reducing effect of the plant constituents (phenols) contained therein.

Thirty-four dairy cows (17 in the spring and 17 in the autumn; average milk yield, 35 kg/d) were fed for six weeks with fresh herbage cut daily and an additional 6 kg of one of three concentrate variants. The concentrate was either grain-based or contained 55% FFPs (corresponding to ­14% of the total diet measured on a dry matter basis), as well as no, or 5%, cocoa bean shells.

FFPs have a season-dependent effect, while CBS have no effect on metabolism or methane production

Feeding FFPs and CBS to cows over a 6-week period had no negative effects on milk yield or metabolism. The concentrate variants had different impacts on fermentation pattern and pH in the forestomachs, in some cases depending on season (spring vs. autumn). Seasonal changes in feed intake, herbage and possibly FFP composition are presumably at the root of interactions between season and concentrate variant. Methane production was unaffected by both concentrate variant and season.

Further clarifications needed

Combinations of herbage and FFPs, and in particular their effects on rumen health, nutrient intake and use by the entire organism including the mammary gland, should be investigated further. The effect on milk yield must also be confirmed over a longer time period and with a greater number of animals. Since the composition of FFPs available on the market generally varies considerably, the implications for dairy nutrition and milk yield should also be investigated in greater depth.