Climate Change Could Be Fuelled By Cattle Drugs

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Dosing farm animals with antibiotics that increase greenhouse gas emissions from cow dung could now fuel climate change.

In a new study, researchers have proved that the antibiotic use on farm animals has unintended, cascading effects on the climate with the production of methane, a powerful greenhouse gas.

Scientists said that the antibiotics boost methane production in cow manure. The antibiotics change the microbes that inhabit dung beetles and also favour the antibiotic-resistant, methane-producing organisms in the gut of the farm animals.

The new paper was published in the Proceedings of the Royal Society B.

The researchers also found that the antibiotics given to the cattle did much more than just increase the greenhouse gas emissions from the cow dung.

Along with increasing the greenhouse gas emissions from the dung, the antibiotics also changed the microbes in the digestive system of dung beetles.

The dung beetles play an important role in cycling carbon and in improving the soil. Also, there was no adverse affect of the drugs on the beetles, as they did not appear to be damaged.

However, there was an adverse affect seen in the antibiotic-contaminated cowmanure, which produced 1.8 times more methane.

The study may be a knock for the farmers, who have been blamed in the past for fuelling antibiotic resistance in humans, increasing air pollution, and fuelling climate change.

Antibiotic Use Still Questionable

However, the present study failed to find widespread support as previous studies have found little or no impact on the dung by the use of antibiotics.

Tobin Hammer from the University of Colorado, one of the authors of the study,told BBC News that some key research questions remained unanswered.

He said,

“Most methane generated by cattle is actually released as burps, and we think that antibiotics are likely to increase burped methane as well – but in this study we weren’t able to measure that directly.

“A second unknown is how generalisable the findings are, across different types of antibiotics.

“Lastly, we don’t know whether, in terms of environmental impact of antibiotics, the problem of methane emissions is outweighed by the benefits of increasing feed efficiency and treating disease.”

Prof Tim Morris, from the University of Nottingham School of Veterinary Medicine and Science, commented,

“Antibiotic misuse needs curbing for many reasons, and the findings in this paper are important where the drugs are being misused.

“However, without undue complacency, these findings should neither distract from more pressing priorities to curb antibiotic use, nor be inappropriately misused on wider questions over agriculture in the UK.”

Even with its limitations, the paper has generated a fair amount of curiosity among researchers.