Existing forage plants may have applications as alternative protein resources for pigs in smallholder farming systems. This thesis examined the effect of harvesting/defoliation interval on the yield and chemical composition of taro leaves and stylo forage and analysed appropriate ensiling methods for these materials. The effect of replacing soybean crude protein (CP) with ensiled taro leaf and stylo forage CP on growth performance and carcass traits of LY (Landrace x Yorkshire) and ML (Moo Lath) pigs was also examined. Taro leaf and petiole dry matter (DM) yield increased with increased harvesting frequency in the two years studied, but there was no effect on tuber yield. The leaves contained 160-260 g CP kg¹ DM. Stylo leaf DM yield was unaffected by harvesting interval in the first year, while leaf DM yield was larger with the most frequent harvesting in the second year. The leaves contained 170-235 g CP kg¹ DM, which was much higher than in the stems or forage (leaves+stems). Use of cassava root meal, sugar cane molasses and taro tuber meal as silage additives affected pH and the DM, ash and NDF content of stylo forage and taro leaf silage, and the NH₃-N content of stylo forage silage. Level of additive affected pH and DM, NH₃-N, CP, ash and NDF content in taro silage, but not NH₃-N, CP and NDF content in stylo forage silage. Increasing duration of ensiling reduced pH and DM content in stylo forage and taro leaf silage. Dry matter intake (DMI) and CP intake (CPI) in growing LY and ML pigs were unaffected by increasing replacement (25 and 50%) of soybean CP by taro leaf silage CP in the diet, whilst for stylo forage silage DMI and CPI were highest when 25% of soybean CP was replaced. Average daily weight gain and feed conversion ratio (FCR), carcass weight, back fat thickness and dressing percentage were unaffected by increasing replacement of soybean CP with taro leaf or stylo forage CP in the diet. LY pigs had higher intake and better carcass traits than ML pigs. The work confirmed that stylo forage and taro leaves can be used as protein sources in smallholder pig production systems without negative effects on the performance of growing LY and ML pigs.
 

Keywords: Harvesting interval, taro leaf, stylo forage, yield, forage quality, taro leaves silage, stylo silage, growth performance, carcass traits