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How a shrub can improve animal health while fighting climate change

 

IDRC-supported research in Kenya has found that a common shrub can have significant benefits for both sheep and the environment.

The research, carried out by a team from the International Livestock Research Institute (ILRI) in Nairobi, has found that the shrub, known as calliandra, not only provides a good source of protein for the sheep, but it also improves the animal’s weight gain and helps build resistance to barber’s pole worm, a common parasite affecting goats and sheep.

In addition, the researchers found that the introduction of calliandra leaves in the sheep’s diet reduced the animal’s daily methane emissions.

Methane, a greenhouse gas, is a product of digestion in the gut of ruminants through a bacterial process called enteric fermentation. The United Nations Intergovernmental Panel on Climate Change identifies greenhouse gas emissions as the primary cause of climate change. The UN Food and Agricultural Organization estimates that the livestock sector contributes 14.5% of global emissions.

Scientists are exploring ways of curbing the greenhouse gas emissions of farming activities, including by altering the diets of livestock, to reduce their impact on climate change. 

Identifying climate-smart interventions 

The ILRI research is being carried out as part of an IDRC-funded project called Livestock keeping in a changing climate. The project aims to generate localized scientific evidence and data on the greenhouse gas emissions of small ruminants in livestock systems in sub-Saharan Africa. It also seeks to provide evidence for potential climate-smart interventions, including improved feeding and manure-management practices. 

The research team conducted an initial experiment to determine the extent of methane emissions by sheep that were feeding mainly on the common grass variety known as Boma Rhodes. Emission levels were then checked again after the animal’s diet was modified. “We changed the animal’s feed to 60% Boma Rhodes and 40% calliandra,” said Paul Mwangi, a veterinarian and member of the team. This change resulted in an 18% reduction in the animal’s daily methane emissions.  

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A man stands in a greenhouse, wearing a white lab coat
Millicent Mwololo/Nation Media Group
Paul Mwangi, a veterinarian and a member of the project team at ILRI.

Calliandra is a plant widely found in western and central Kenya. It can also be grown as a hedge. The project team led by Cesar Patino, a ruminant nutritionist, believe that calliandra’s high protein content (between 20% and 25%) and its condensed tannins (a secondary metabolite produced by plants with antibiotic, antifungal and antiviral properties) are responsible for the benefits identified through the research.

Some commercial farms with sufficient financial means buy blended feeds that give the animal enough proteins, but not all farmers can afford to do so. By providing a low-cost protein supplement, calliandra would be beneficial to farmers like Gideon Parsanga, in Kenya’s water stressed Kajiado county.

“We all feel the effects of climate change,” said Parsanga. “For us, the Maasai, we have lost thousands of livestock to the ongoing drought.”

While the team’s work involved only sheep, Mwangi and Patino are optimistic that using calliandra as a readily available protein source may be applicable with other livestock ruminant species. 

Learn more about the project