How grass affects cattle greenhouse gases

Tuesday May 29 2018

A farmer chops napier grass for her dairy cow and goats. Scientists are testing Napier, Rhodes and Brachiaria grasses for cattle feed to determine actual agricultural greenhouse gas emissions. FILE PHOTO | JOSEPH KANYI


Scientists could soon tell actual agricultural greenhouse gas emissions in sub-Saharan Africa by testing different animal feeds.

A team of researchers at International Livestock Research Institute (ILRI) are testing Napier, Rhodes and Brachiaria grasses for cattle feed, and then physically measuring the emissions in a respiration chamber within the institute’s laboratory.

“The study will help African countries monitor, measure, verify and report their emissions with the aim of reducing their nationally determined contributions [NDCs],” said ILRI principal scientist Klaus Butterbach-Bahl.

NDCs are measures that countries are taking to help reduce global greenhouse gas emissions as stipulated under the 2015 Paris Agreement on climate change.

Mr Butterbach-Bahl said that accurate estimates of greenhouse gas emissions from livestock will help assess the efficacy of mitigation measures by each member country.

“The measurements will help find better locally available tropical feed for the region as opposed to overreliance on feeds from the temperate world,” he said.


The ILRI study, which started three weeks ago, is the first of its kind on the continent. It involves 18 cows of Boran breed, and will go on for the next five months.

Findings will be shared with other countries in sub-Saharan Africa following a peer review.

According to Daniel Korir, one of the researchers, the study is also testing the best way to grow the grasses.

“The temperate forage in sub-Saharan Africa is low in fibre, highly digestible and high in protein while that in the tropics is high in fibre and low in protein,’ said Mr Korir.

It is estimated that more than 70 per cent of African agricultural greenhouse gas emissions are due to livestock production, dominated by emissions from enteric fermentation, a process in which the animals produce methane through digestion. 

According to the Intergovernmental Panel on Climate Change, Africa accounts for 3.8 per cent of global greenhouse gas emissions, compared with the largest emitters China, the United States, and the European Union, that account for 23, 19, and 13 per cent respectively. But the continent is also highly vulnerable to climate change.