March 8, 2022

Australian university researcher highlights ruminants' role in turning waste into food

The role of ruminant livestock as convertors of waste products into protein is often overlooked in greenhouse gas calculations, University of New England (UNE; Australia) livestock nutritionist and modeller Dr. Holland Dougherty said.

Dr. Dougherty addressed the 2022 Agritech Futures Series this month, making the point that byproducts from human food and fibre crops make up about a third of livestock diets globally.

"If we didn't have livestock to upcycle these products, we would have to find another use for them," Dr Dougherty said. "And for some of these byproducts, there's not many other uses – or if there are other uses, they don't contribute to the human food supply.

"The sustainability metrics we use don't tend to capture this symbiosis, where ruminants make it possible to turn waste material into food rather than us losing that material out of the food cycle."

Dr. Dougherty was one of seven speakers at the Agritech Futures seminar. She said that the scientific literature is deficient on the subject of upcycling.

With other UNE scientists, she hopes to launch a research project that will correct the deficiency.

She said: "Across the world, we use livestock to clean up our messes. For every 100 kilogrammes of food we produce, about 37 kilos of byproducts are produced that can be fed to livestock – and that's exactly what farmers tend to do."

"What would happen to the numbers if livestock were not there, converting crop waste to protein? If that material was actually wasted, or used outside our food supply? What would be the greenhouse gas penalty of producing more food to replace that protein we now grow on crop byproducts?

"We still need more of a big-picture perspective on the role of livestock. I think it's really vital that we get that information, both to better understand our food production systems, and to guide policy around climate change."

- UNE