Taking stock of the evidence for more climate-friendly cows

16 September 2022 | News

After chewing over solutions for reducing dairy cows’ impact on the environment, Dr Cameron Marshall is celebrating his graduation from Lincoln University this year.

Cameron’s PhD research has crucial implications, as it shows that some cows are genetically predisposed to cause less harm to the environment than others and farmers can potentially use the findings to breed more climate-friendly animals.

His acclaimed research earned him a Doctoral Scholarship in 2019 and the grand prize in the 2020 Lincoln University Three Minute Thesis Competition.

He's now bringing his considerable expertise to a position at Lincoln-based company, Leaft Foods, which is working on developing edible protein from leafy crops grown by local farmers.

First completing a Bachelor of Agricultural Science at Lincoln University, Cameron quickly progressed to a PhD, wanting to help lead the way towards more sustainable farm systems.

Inefficient nitrogen use in pastoral production systems was creating concern about environmental degradation, with excessive nitrogen leaching from dairy cows’ urine into waterways and nitrous oxide emissions entering the atmosphere from urination patches.

“Cows are demonised for it,” Cameron said. “But they can be part of the solution too.”

His research shows that dairy cows with a specific low milk urea nitrogen gene will urinate less nitrogen than others by up to half.

Most herds will already include cows that are high for this particular trait, which can be identified through the testing of milk, giving farmers the option to breed from their pre-existing stock and change the make-up of their farm over time.

In one of Cameron’s studies, cows with the gene that were fed plantain rather than ryegrass excreted significantly less nitrogen during urination, reducing leaching into waterways.

Another study found that the grazing and ruminating behaviour of cows selected for divergent milk urea nitrogen tended to chew differently, which could alter nitrogen digestion and subsequent excretion to the environment.

The results of his research present promising solutions that could be used to reduce nitrogen losses and alleviate environmental impacts.

Cameron has the opportunity to attend the Lincoln University Graduation Celebration in the Christchurch Town Hall on 23 September to mark his achievements.

Although he already received his PhD earlier this year, the event was organised to acknowledge the hard work of Lincoln’s 2022 graduates, following the cancellation of the original ceremony in May due to COVID-19 restrictions.

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