In Laos, commercial pig farms are found near population centres
such as Vientiane. These agribusinesses are small cottage
industries with few employees. In general, production costs tend to
be high, since semi-intensive pig production is dependent on
concentrate feed which, in many cases is imported from Thailand.
Concentrate feeds are mixed with locally available feeds such as
rice bran and brewers' grains to reduce production costs (Stur et
al 2002). In view of the high production costs, because of the
increasing prices of concentrate feeds, and especially protein
concentrates such as soybean and fish meal, recent research in
Vietnam, Cambodia, and Laos has been directed to the use of leaves
from crops such as cassava (Hang and Preston 2005; Chhay and
Preston 2005), sweet potato (Chittavong and Preston 2006) and
mulberry (Cheiv et al 2003), and water plants such as water spinach
(Men et al 2000; Ly 2002) for feeding pigs and supplemented with
local energy feed resources such as sugar cane juice, cassava root,
palm oil and broken rice (Rodríguez et al 2006; Chhay and
Preston 2006; Kea et al 2003). All these energy feed resources are
very low in protein content in the dry matter and as a consequence
of this all the amino acids in the diet have to be supplied in a
protein supplement (Preston 1995).
Leaves from Taro (Colocasia esculenta (L.) Schott), Giant taro (Alocasia macrorrhiza), and New Cocoyam (Xanthosoma sagittifolium) are traditionally used in pig diets by small-scale farmers in many tropical countries. A preliminary report from Colombia (Rodríguez et al 2006) showed that weight gains in young pigs fed a sugar cane juice diet were the same when the supplementary protein was from a 50:50 mixture of fresh leaves of New Cocoyam and soy bean meal compared with soy bean meal as the only protein source. Also results from Tiep et al (2006) show that including 10% ensiled Alocasia macrorrhiza leaves (replacing fish meal and soybean meal) with 45% Alocasia macrorrhiza root meal in diets for crossbred (Yorkshire x Mong Cai) pigs had no negative effects on performance, and resulted in higher benefit for the farmers in mountainous areas in Northern Vietnam.
Water spinach (Ipomoea aquatica) is a water/marsh plant
which grows well in the water or in the soil. It is traditionally
consumed by people in South East Asia and appears to be devoid of
non-nutritional elements. The fresh leaves and stem of water
spinach have a crude protein content of 28 % of DM (AFRIS 2005). It
has been shown that fresh, chopped water spinach can replace 30% of
the DM of concentrate diets for gestating sows and 15% of the diet
of lactating sows of both local (BaXuyen) and exotic breeds (Large
White), resulting in somewhat improved reproductive performance and
welfare (Men et al 2000)
To determine the optimum level of molasses additive for
ensiling taro leaves
To evaluate the effect of protein-rich leaves as replacement
for soybean meal on the performance of Mong Cai gilts during
gestation and lactation
To determine the apparent digestibility coefficients in the
early and late stages of gestation in Mong Cai gilts fed ensiled
cassava roots and broken rice with protein derived from different
ratios of soybean meal and a mixture of taro leaf silage and water
spinach