The aromatic smell and unique taste of steaming sweet potatoes is a favorite food for many Chinese and African food lovers, but it seems that the nutritious vines of the vegetable have other valuable uses.

The International Potato Center (CIP) has rolled out the use of sweet potato vines as a low-cost alternative of feeding livestock in East Africa.

Orange-fleshed sweet potatoes present farmers with a feed option as the plant's vines offer more protein and dry matter per unit growth area, requiring less land than other commonly used livestock feeds in Kenya, Uganda and Rwanda. The sweet potato root needs to be cooked before its nutritional value is optimized, making the laborious process for livestock use unviable. The vines therefore are an ideal way of maximizing use of the crop.

The CIP program aims to improve food security through increased growing of the sweet potato, as the plants root, which is rich in vitamin A is consumed by people, and the vines can be used to feed livestock after harvesting of the crop.  Despite its appearance, the sweet potato is classified as a storage root unlike the potato, which is a tuber.

East Africa has the highest per-capita consumption of dairy cattle, pig and goats for meat and milk in sub-Saharan Africa. The challenge facing farmers is increasing the cost of commercial quality feed concentrates.

Ramping up sweet potato production will provide an alternative feed for farmers, as researchers of CIP, along with other partners involved in the project, say 4 kg of vines could replace 1 kg of dairy feed concentrate, making the vines more cost-efficient.

The East African Dairy Development Project, University of Nairobi Department of Animal Production, Egerton University, Farmer's Choice Ltd. and Rwanda Agricultural Board Research already have experience working with farmers.

Dr. Jan Low, leader for Sweet Potato for Profit and Health Initiative (SPHI) at CIP in Nairobi, said the program has produced outstanding results as farmers are taught to make silage using sweet potato roots and vines.

"Napier grass which is used as a primary feed for dairy farming requires significant allocation of land, and major shortages occur during the dry season, leading to reduced milk production," she said.

Once sweet potatoes are harvested, the vines are dehydrated to reduce moisture content. The roots and vines are then chopped, mixed with supplements and stored in airtight plastic bags.

Dr. Ben Lukuyu of International Livestock Research Institute (ILRI) said the sweet potato's potential as animal feed is promising, as the project's aim is to give farmers strategies to best respond to their needs and demands.

In China, sweet potato is widely cultivated in Sichuan Province, especially in hilly or mountainous regions. Overall, more than 95 percent of vines and 60 to 70 percent of tuber roots of the province's total production go to pig feed.

As sweet potatoes are harvested once a year, and vines and tubers are easily perishable, preserving the crop as fodder was identified as a major concern by an animal systems research network project implemented by ILRI from 2002 to 2005.

In 2008, more than 90 million fattening pigs were sold in Sichuan Province, of which about 70 percent were from rural households. Sweet potato pig systems play an important role in smallholders' livelihood strategy in that province.

ILIRI and CIP with other stakeholders are working with dairy and pig farmers in East Africa in participatory research to test viability for using sweet potato vines as fodder and leaf protein supplements.

CIP's sweet potato expert Agili Sammy said the project has also addressed a major challenge for smallholder farmers in accessing disease-free planting material.

"Sweet potato is the third most important food crop in East Africa. It can produce better yields in poor conditions with fewer inputs and less labor than other staples, making it suitable for most households," he said.

In addition to the orange fleshed sweet potato adding value to animal feed, the root is rich in vitamin A whose deficiency threatens an estimated 43 million sub-Saharan children under age 5.

The sweet potato is rich in vitamin A, B and C and potassium. But in sub-Saharan Africa, the United Nations Conference on Trade and Development said about 32 percent of the population suffers from vitamin A deficiency which can lead, amongst others illnesses, to blindness and premature death in children and pregnant women. With its high nutrition rating, the sweet potato can therefore be a valuable staple food.

Locally-adapted sweet potato varieties resistant to drought and disease have been developed to meet consumer and producer preferences.

The sweet potato is still considered an exotic crop in many countries, due to difficulties in commercializing the plant and then storing and conserving the crop. It therefore does not traditionally attract much investment.

However with many years of CIP's experience in China and other parts of Asia, such as Viet Nam and Indonesia, this plant could prove to be a long-term solution for Africa's livestock feed and also as an important source of nutrition for humans.

(Reporting from Kenya)