by
Center for Livestock and Agriculture
Development
buntha@celagrid.org
Fattening pigs are one of the major sources of farm cash income for rural farmers in Cambodia. Generally, piglets are purchased after the rice harvest at a live weight of 4-6 kg and then reared for 8 to 10 months. The reason for buying the piglets in this time is that farmers will have enough money and feed available from rice by-products. The traditional feeding practices depend on the available feed resources in the region. The low performance of pigs in the traditional production system is basically a result of the poor quality and availability of feed resources and insufficient feed supplements. There are also other important factors that affect production, such as management, breed and mortality caused by infectious diseases and parasites. Normally one to two pigs are commonly raised for sale or for ceremonial purpose e.g. wedding banquets (Khieu Borin1996).
According to Preston (2006) the leaves from shrubs such as cassava and mulberry, and from vegetables such as sweet potato and cocoyam, together with water plants such as duckweed (Lemna spp) and water spinach (Ipomoea aquatica), can be used successfully in diets for pigs to replace at least half the protein usually supplied as soya bean and fish meals.
Taro or cocoyam (Colocasia esculenta Schott), which originated in India and South East Asia, is presently cultivated in many tropical and subtropical countries. The level of crude protein, although slightly higher than that in yam, cassava or sweet potato, contains low amounts of the amino acids histidine, lysine, isoleucine, tryptophan and methionine (AFRIS 2004). Taro can be harvested between 6 and 13 months after planting, depending on the incidence of pests, and soil and weather conditions that could cause early maturation (Miyasaka et al 2003).
Taro, locally known as trav, is divided into land trav and water trav, which are cultivated or grow wild in different agro-ecological regions of Cambodia. The cultivated taro is primarily as a vegetable food for its edible corm, and secondarily as a leaf vegetable. Its flowers are also eaten. However, a few farmers use the stem after boiling with broken rice in diets for pigs, while the leaves are normally discarded or used as green manure in the fields. Around Phnom Penh City taro was found growing on polluted lake water, and the stem and leaves were harvested daily by people from other provinces for sale at 2500 riel (0.6$) per bunch (25 kg). In the rural areas, farmers plant taro near the house or rice field as a vegetable for human use. It is normally planted in the wet season and harvested in the dry season. Taro is a locally available feed resource with good potential for animals, especially for pigs, because of its nutritional quality. According to FAO (1993) the leaves of taro contain 8.2% DM, 25% CP, 12.1% CF, 12.4% Ash, 10.7% EE, 39.8% NFE, 1.74% Ca, and 0.58% P. However, there are difficulties in using taro as animal feed because of its content of oxalic acid and other anti-nutritional factors that cause the mouth and throat of animals consuming it to itch. However, some local farmers traditionally reduce the oxalate content by boiling, and scientists have found new methods for reducing the oxalate acid, such as drying, ensiling, or using chemicals.
Several studies on the use of taro for pigs have been carried,
but have focused on the root (Agwunobi et al 2002; Tiep et al 2005;
Tiep et al 2006). Few studies have been done on using fresh taro
leaves for pigs (Rodriguez et al 2006).
These studies focused on the effect of using ensiled taro (Colocasia esculenta) leaves as replacement for fish meal in diets for local crossbred pigs. A survey was done to collect information about the varieties and cultivation of taro and their uses in Cambodia (Paper I) and a trial was carried out in order to determine the digestibility and nitrogen balance for pigs of diets with ensiled taro (Colocasia esculenta) leaves replacing fish meal (Paper II). A growth trial was also carried out to determine feed intake, growth rate, feed conversion ratio and economic benefits in crossbred pigs fed ensiled taro leaves replacing fish meal, with rice bran and sugar palm syrup as energy sources (Paper III).