Around 40% of the US’ total food supply goes to waste, making food the largest single source of waste in US landfills.
At the same time, around 35 million Americans – including 10 million children – are affected by food insecurity, with more than 80% of shoppers admitting they discard food because they misjudge expiration dates.
Add to that a national goal to halve food waste by 2030, and it’s clear that the food industry is under increasing regulatory pressure to contribute to a less wasteful food system. US dairy has long campaigned to improve relevant policies around safety dates and labelling among other initiatives, but there may well be a way for some producers to make their contributions more immediate.
Recently published Pen State University research demonstrated that unsold supermarket goods – such as fruit, vegetables and bakery goods – could safely replace a part of the dairy cattle diet without impacting milk production and quality. The intervention also led to improved fibre and fat digestibility and points toward potential savings on feed.
The experiment was carried out in 2018 and involved 48 Holstein cows, which were fed diets where recovered grocery waste replaced corn and molasses at rates of 7.5% and 15% of total dry matter intake. The trial ran for 40 days, with researchers tracking feed intake, milk yield, milk composition and nutrient digestibility over time.
The intervention was largely positive – with a slight drop in milk yield during the initial adaptation period – while the diet’s overall nutrient profile remained largely unchanged despite the shift in ingredients. Importantly, despite the experimental feed’s low pH, the acidity did not disrupt rumen function while helping keep the feed stable during storage when held for several days before feeding.
The experiment offers an example of how unsold goods could be repurposed into animal feed, potentially paving the way for retailer-producer partnerships that can positively contribute to lowering food waste.
However, the study has several limitations. The recovered food sourced for the experiment was highly diverse – a mix of unsalable fruits and vegetables, some bakery products, and some fruit and vegetable processing waste – meaning that its composition varied, impacting the precision of ration formulation. The trial was also short, at just 40 days, so long-term health and reproductive impacts have not been examined.
But overall, the findings suggest that, with careful management, grocery waste could offer a viable and scalable way to cut feed costs, improve resource efficiency and reduce the environmental impact of dairy production.
Source:
Effect of recovered grocery food substituted for corn grain and molasses on milk production and total tract digestibility in lactating dairy cows
Bomberger R, et al
Journal of Dairy Science, June 23, 2026
