Tran Thanh Hai, Nguyen Thi Hoa Ly and Preston T R  2012 Effect of replacing fish meal by a mixture of  ensiled taro (Colocasia esculenta) foliage and  sweet potato vines (Ipomoea batatas L.) on reproduction and piglet performance in VanPa  sows in  central Vietnam. Proceedings of the International Conference "Livestock-Based Farming Systems, Renewable  Resources and the Environment", 6-9 June 2012, Dalat, Vietnam (Editors: Reg Preston and Sisomphone Southavong) http:/www.mekarn.org/workshops/dalat2012/html/hoaly.huaf1.htm