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Netting flies and mosquitoes protects livestock, boosts milk yields

Insecticide-treated nets control pests in animal shelters, reduce mosquitoes in homes

Photo: ©FAO/Simon Maina
Black insecticide-impregnated nets encircling livestock pens kill disease-carrying mosquitoes and flies

27 March 2013, Rome - A simple but innovative use of insecticide-impregnated nets to protect livestock is doubling and in some cases tripling milk outputs on smallholder dairy farms while also reducing mosquito-borne illnesses in humans in Kisii, Kenya, in the country's western highlands. The FAO project is part of a wider strategy to vastly improve animal health in areas most affected by tropical diseases.

The nets are environmentally safe and have drastically cut the number of flies, mosquitoes and other disease transmitting insect vectors by close to 90 percent, and cases of mastitis, a bacterial disease that can be spread by flies as well as poor hygiene during milking, have been halved on smallholder dairy farms. Farmers also learned basic hygiene measures to reduce illnesses in their cows.

And the mosquito nets are having a significant knock-on benefit for families: in Kisii, preliminary results show that farmers are reporting 40 percent fewer cases of malaria in their homes. While Kenyans often attribute illness to malaria without knowing the true cause, a direct human health benefit shouldn't come as a surprise.

One farmer in the Kisii area, Mary Munyega Nyandeo, said, " I used to milk around 2 litres of milk, but since the nets were brought and the flies disappeared, I now milk around 4 or 5 litres a day, so I make profit."

What's more, she said, "we've had no more malaria."

Another farmer, Mary Owendo, said, "Before this, I thought milk was only for the home. I never knew that selling milk could help me pay my children's school fees." She even managed to pay to get electricity in her home, thanks to the cows.

From open grazing to zero grazing

In recent decades, as available land has shrunk due to urban expansion or as land is diverted to other uses, smallholder farmers have increasingly adopted the ‘zero grazing' model, in which dairy cows are fed in well-ventilated shelters, rather than being allowed to roam in open pastures. In Kisii, farm after farm has switched to this method as smallholders farm on smaller and smaller plots. The challenge, however, became managing the increasing fly and vector populations that were drawn to the sheds with the zero grazing cows and the waste pits associated with them.

"These ‘site-specific animal health packages' with nets to protect the cow shelters and the waste pits have proved not only effective in maintaining the area's freedom from biting flies and mosquitoes, but they also improved animal health across the board," explained Rajinder Saini, an entomologist with FAO's implementing partner in Kisii, ICIPE, an international research institute based in Nairobi. ICIPE no longer goes by its original acronym, branding itself now as "African Insect Science for Food and Health."

"Now the cows are happy, they don't waste energy stomping their feet and flicking their tails, and they are converting feed better, gaining weight and producing more milk. The farmers are obviously happy too," Saini said.

The human health benefit, everyone agrees, would be the natural added benefit of reducing the numbers of the same vectors that transmit illnesses to humans, sometimes from their own livestock animals.

Dying off like flies

"In my first years in Africa, I'd look around and see especially the exotic breeds of animals dying off by the droves," said Burkhard Bauer, an independent Senior Scientific Advisor of the Free University of Berlin working on the FAO project. The project is built mainly upon the use of insecticide netting to make smallholder farms fundamentally healthier, even in resource-poor settings.

Bauer first went to Kenya in 2001, where he managed an EU-funded project on dairy farming in zones where tsetse fly populations are a problem. Tsetse flies transmit the disease trypanosomosis or nagana to animals, which is responsible for the deaths of 3 million cattle and economic losses of more than $4.5 billion every year in sub-Saharan Africa. The disease when transmitted to humans is better known as ‘sleeping sickness,' and it is inevitably fatal in humans when left untreated. Some 30 000 people contract the disease in Africa every year, and it is a significant impediment to economic development in so-called T&T (tsetse and trypanosome) zones across Africa.

In countries like Kenya, where smallholders owning just one or a few cows care for 80 percent of the dairy animals and produce more than three-quarters of the country's milk, the loss of an animal can devastate a family economically.

"We were treating animals that were already sick, but they kept dying. So we needed to look at the real culprits - the insects that transmit disease in the first place," said Bauer. Bauer's concept, with support from the university and partners like FAO, has been tested in the field and honed over time.

He said it was so simple, he couldn't believe no one had thought of it before.

Ecologically sustainable

The insecticide nets have also been shown to be ecologically safe. Minimal netting is used, in addition, since tsetse flies generally fly close to the ground. So just one metre in height around livestock shelters needs to be protected with the netting.

"The insecticide used is made from the same chemicals used in pet flea collars," said Raffaele Mattioli, Senior Officer with FAO's Animal Health Service in Rome.

Livestock are typically dipped into water treated with pyrethroid insecticides, since they don't affect mammals. Or farmers slather it over their legs. But with the nets, only the exact necessary amount of that chemical is impregnated in the nets and constantly released over time - minimizing the risk that insects will develop resistance to the insecticides. Pyrethroids are now the main insecticides on the market for household use.

The insecticide-impregnated nets also potentially eliminate ticks, by modifying for example the amounts of insecticide used and ensuring the nets come into contact with the ground. So tick-borne diseases, such as East Coast Fever, which is widespread in Eastern Africa, could be reduced with the same basic approach, Mattioli said.

"This project, though conceived to increase animal health and production, is a concrete example of a One Health approach, where interventions to improve health - whether animal or human merges and is a product of a larger system of interlinked healths - including also plants and the ecosystems they all live in," said Mattioli.

Scaling up and out

Smallholder pig farmers are also using the livestock protective net fencing in Ghana. The biting of nuisance flies has been reduced nearly to zero and pig production and health has improved. The work in Ghana is done in coordination with the country's national coordination office of the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC). A third pilot is getting underway in Burkina Faso, where the livestock systems are predominantly pastoralist.

In recent project meetings, government and private sector trainees interested in emulating the model have also learned about use of the insecticide nets. The trainees were from Burundi, Eritrea, Ethiopia, Kenya and Rwanda in Eastern Africa and from Benin, Burkina Faso, Cote d'Ivoire, Ghana, Mali, Niger, Nigeria, Sierra Leone and Togo in Western Africa.

The pilot projects are supported by $1.6 million in funding from the International Fund for Agricultural Development (IFAD).