How roasting beans for beef rations improved liveweight gain

Feeding roasted beans increased average daily liveweight gain by 0.15kg, when compared with using unroasted ones, in rations for young bulls on a mixed farm in South Yorkshire.

In addition, carbon emissions were 0.5kg lower for each kilogram of liveweight gain.

John McArthur, who farms at Briar Farm near Doncaster with his mother Jane, got the idea to roast beans from a dairy project in Denmark.

He decided to run an on-farm trial to see the potential benefits for his beef cattle.

See also: Pros and cons of feeding a home-grown dairy ration

“I visited an organic dairy farm that was processing home-grown beans as part of an effort to reduce reliance on imported soya,” explains John, who runs a herd of 40 spring-calving sucklers alongside an arable enterprise.

“By roasting the beans from a high moisture [content], they were preserved for long-term storage,” he says, adding that the Danish farm also found significant improvements in bypass protein and starch.

“This supported an increase in the cows’ metabolisable protein supply.”

Beef system

The herd at Briar Farm spends the summer months grazing permanent pasture alongside the River Don and is housed from about October to March.

Progeny are reared for sale as stores, with timing of selling decisions based on market prices.

In 2024-25, all youngstock were reared on-farm and sold at the spring markets as forward stores.

“The prerogative of a mixed farm is being able to choose your priority according to market conditions.

“This year, rearing more of the youngstock made sense as it was the best way to add value to our barley and beans,” says John.

Feed trial

Keen to see if he could also improve the feed value of the beans, he set up a small-scale feeding trial under the guidance of beef nutritionist Lizz Clarke of LC Beef Nutrition.

The trial formed part of the ongoing Nitrogen-efficient plants for Climate Smart arable cropping systems (NCS) project (see “Project details and farmer opportunities”).

Tests by the Flanders Research Institute for Agriculture, Fisheries and Food as part of the NCS project had shown that roasting beans increased rumen undegradable protein by up to 100%.

Protein digestibility in the small intestine increased by 4%.

Roasting also increased bypassed starch by up to 47%, while digestibility was unaffected.

© John McArthur

The trial at Briar Farm involved dividing the farm’s 2024 crop of 26 weaned bull calves (averaging 322kg at eight to 10 months old) into two groups of 13 animals.

Over the following 126 days, both groups were fed ad-lib grass silage, 5kg a head a day of rolled barley and 1kg a head a day of faba beans – all home-produced – plus 0.08kg a head of bought-in minerals.

One group received rolled beans, while the other had beans that had been roasted and rolled.

“The beans were harvested dry and stored in the grain store,” explains John, who also has a diversified farm business, McArthur BDC, which designs, builds and maintains grain drying, storage and processing equipment.

“From there, we used an auger to load them into the toaster. They are then exposed to high temperatures for a relatively short time.

“The idea is that the process improves the metabolisable protein available to the animal. It also improves palatability, taking away any bitter taste.”

Higher daily liveweight gain

While it was not possible to quantify any increased intake, John could see that the group receiving roasted beans were particularly keen.

“They’d want to get their noses straight into the bucket of beans as soon as they saw it,” he says.

Yet, monthly weighing during the trial showed higher daily liveweight gain (DLWG) in the group fed roasted beans.

“At first, the weigh-ins weren’t indicating much of a difference, but by the end of October, the roasted bean group really started motoring. By the end of March, the difference was clear,” says John.

© John McArthur

Average DLWG for the group receiving the roasted beans was 1.54kg compared with 1.39kg for the control group – an 11% improvement.

“Our diets were formulated by Lizz and based on achieving 1.4kg daily liveweight gain, so we can see the roasted beans increased that, resulting in a lower feed conversion ratio,” he says.

Most of the top-performing animals in the trial – which reached 2.1kg DLWG – were in the roasted bean cohort, he adds.

Lower carbon footprint

Carbon footprinting by Farm Carbon Toolkit showed that, because of the heating process, carbon emissions were higher for the roasted beans, at 171kg/t, compared with 162kg/t.

The feed also worked out £4.50/t more expensive.

Despite this, the higher DLWG reduced the overall feed cost of rearing by 5p/kg liveweight gain, from 98p/kg for the control group to 93p/kg for those fed the roasted beans.

Carbon emissions were also lower for the roasted bean group, at 6.11kg carbon dioxide equivalent/kg liveweight gain, compared with 6.61kg.

“In short, the feed is a bit dearer, but the better performance brought cost of production down as well as carbon emissions, improving overall productivity and profitability,” says John.

Next steps

Lizz is overseeing trials on other beef farms as part of the project, and John intends to run another on his farm this autumn.

“There’s a wide range of trials taking place, all with the aim of finding ways to get the best from beans in the livestock diet,” says John, whose grain storage business is one of 17 partner organisations in the NCS project.

“Ours is only a small farm trial and needs to be replicated in larger systems, but the results are really encouraging.

“The gains we can make as an industry from reducing our dependency on soya are immense.

Updated figures from the NCS project suggest that we can make savings of 3.4Mt of carbon by increasing production of pulses to 20% of the total arable area and replacing 50% of imported soya with home-grown pulse products,” he says.

He adds that beef rations at Briar Farm are now entirely home produced (apart from minerals) and soya-free.