Calliandra: The shrub that fattens sheep, blocks worm infestation, and fights climate change


Sheep inside the respiratory chamber, which was used to measure the methane gas emissions levels during the experiment at the Mazingira Centre in the International Livestock Research Institute (ILRI) in Nairobi.

Photo credit: Millicent Mwololo| Nation Media Group

Balanced nutrition is good both for animal health and for lowering greenhouse gas (GHG) emissions, scientists have found out.

A team of researchers based at the International Livestock Research Institute (ILRI) in Nairobi, using calliandra shrub as a protein source, have found incredible benefits the plant has on sheep.

Generally titled ‘Livestock Keeping in a Changing Climate’ the project had two key objectives.

The first was to determine the effect of worms on methane emission by sheep. The second was to establish how calliandra improved animal health as well as its effect on methane emissions.

Methane, a greenhouse gas, is a product of digestion in the gut of ruminants. The United Nations Intergovernmental Panel on Climate Change (IPCC) identifies GHG emissions as the primary cause of climate change.

The team conducted an initial experiment to find out the extent of methane emissions by sheep feeding mainly on the common grass, also known as Boma Rhodes.

“In the first experiment we collected data on the animal’s live weight, level of infection with Haemonchus contortus (commonly known as barber's pole worm), and levels of methane emission, among others.

“We did this with two breeds of sheep: the indigenous Red Maasai and the Dorper. Looking at the parameters, we wanted to establish any differences between the two breeds,” says Dr Cesar Patino, the lead scientist in the project and a ruminant nutritionist.

Paul Mwangi

Dr Paul Mwangi, a veterinarian and a member of the team in the ‘Livestock Keeping in a Changing Climate’ project. Photos taken during the interview at the Mazingira Centre in the International Livestock Research Institute (ILRI) in Nairobi.

Photo credit: Millicent Mwololo / Nation Media Goup

The team established that Dorpers produce more methane: on average 12.5 per cent higher methane yield, measured as grams of methane per unit of feed intake, than Red Maasais.

They also discovered that the local breed had developed better resistance to barber’s pole worm compared to Dorper sheep.

Barber's pole worm is a common parasite known to be extremely pathogenic to ruminants. The worm causes anaemia and hampers production at the farm.

The first experiment informed the design of the second experiment.

“Having established that the Dorper is more susceptible to barber’s pole worm and generally produces more methane, in the second experiment we wanted to see how introducing calliandra as a feed would alter the dynamics – using the Dorper,” says Dr Patino.

Calliandra – a leguminous plant with high protein and condensed tannins (a secondary metabolite) content – is a common shrub common in western and central Kenya. It can also be grown as a hedge.

“We changed the animal’s feed to 60 per cent Boma Rhodes and 40 per cent calliandra,” says Dr Paul Mwangi, a veterinarian and a member of the team.

The researchers found that the introduction of calliandra reduced the animal’s daily methane emission by 18 per cent. Looking at methane emission per unit of feed, the reduction was even bigger at 30 per cent.

Importantly, for a farmer, introduction of calliandra resulted in 80 per cent reduction in faecal worm-egg deposits.

This means that worm infestation had reduced. Indeed, the animal had 17 per cent higher red blood cell volumes compared to results from the first experiment

The animal also more than doubled the rate of weight gain; resulting in 225 per cent higher live weight gain while increasing its feed intake by just 14 per cent; perhaps an indication of better digestion and assimilation of feed.

For farmers like Gideon Parsanga from Oloelelai in Kajiado County, these findings offer solutions to remedy worm infestation, improve live weight gain, and practice climate smart agriculture.

Dr Cesar Patino,

Dr Cesar Patino, the lead scientist in the ‘Livestock Keeping in a Changing Climate’ project and a ruminant nutritionist at the International Livestock Research Institute (ILRI) in Nairobi. Photos taken during the interview at the Mazingira Centre in ILRI.

Photo credit: Millicent Mwololo / Nation Media Group

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

Dr Patino and his colleagues believe that calliandra’s high protein content (of between 20 and 25 per cent) as well as its secondary metabolites – specifically condensed tannins – are to thank for results.

Unlike calliandra, the boma Rhodes used in the experiment had a protein content of 7 per cent.

“Ideally, good quality grass for livestock feeding should have protein content of about 15 per cent,” says Dr Mwangi.

Modern commercial farmers like Isaac Kosgei, the founder of Kibois breeders, buy formulated feeds that give the animal enough proteins.

“We supplement with wheat bran, maize jam, cotton seedcake, silage and other feed formulations,” he says.

But the likes of Parsanga do not have the wherewithal for such heavy financial undertakings.

“Calliandra would be a low-cost protein supplement for farmers. Beyond lowering an animal’s methane emissions, the shrub has extra benefits to the farmer: namely, it fixes nitrogen in the soil and reduces worm infestation,” says Dr Mwangi.

Though not yet published, the team’s work is important because the livestock sector contributes 14.5 per cent of GHG emissions according to a 2013 study published by Food and Agricultural Organisation (FAO).

The project was funded by the International Development Research Centre (IDRC Canada).

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