Growth performance of lambs in Phangrang, Vietnam: effects of a dietary supplement containing prickly-pear cactus.

In Phanrang, Vietnam, sheep production is limited by the sparse availability of green roughage. Although prickly-pear cactus (Opuntia elator) is abundant in the area, it is not used. It was considered relevant therefore to test whether prickly-pear cactus could be used a component of feed supplements. With the use of the cactus and other local products--namely groundnut cake, fish sauce by-product, molasses, rice bran and cassava flour--two supplements were prepared. The level of cactus in the two supplements was 670 g/kg product (320 g/kg dry matter). The cactus was burned to remove the spines, chopped and sun-dried before use. The cactus preparation contained only 12 g crude protein/kg (68 g/ kg dry matter). The protein content of the two supplements was raised with either groundnut cake or fish sauce by-product. Sheep that were grazing during the day were offered either no supplement or one of the supplements when confined during the night. During a period of 3 months, non-supplemented control sheep gained 98 +/- 10.5 g/day (mean +/- SD, n=10). Sheep supplemented with cactus and groundnut gained 145 +/- 12.3 g/day, and those given cactus and fish sauce gained 130 +/- 11.7 g/day. It is concluded that prickly-pear cactus has potential as component of feed supplements for sheep.