Strategies for improving the nutritional status of small ruminants in tropical ecosystems

Abstract

Research on goat and sheep nutrition and feeding systems has been initiated in five tropical or Mediterranean countries, by United States and host-country institutions which are participants in the Small Ruminant Collaborative Research Support Program. The major objective is to increase small ruminant productivity by better utilizing locally available feedstuffs and to more closely meet the nutritional needs of animals during the critical phases of their production cycle. West Java, Indonesia, is a humid tropical site with high rainfall and intensive agriculture, with small ruminants raised in nearly total confinement. Village feed resources include native grasses, tree legumes, and foliage from food crops. Energy may be the most limiting nutrient, due to seasonal feed availability and intake limitation when tropical grasses form a large proportion of the diet. Western Kenya is a wet-dry tropical site with a long and a short rainy season. The feasibility of intensifying dual purpose goat production within mixed crop-livestock systems is under study. Solutions to severe dry season feed limitations are being evaluated. Sweet potato vines and legumes such as pigeon peas have been demonstrated to be excellent in nutritional value, with high intakes by lactating does. Intercropped or ratooned sorghum also has promise. Northeast Brazil is representative of the semiarid tropics with a short, variable rainy season and prolonged dry season during which all production parameters for goats and hair sheep are unsatisfactory. The native “caatinga” brushland is the major feed resource. Dry season confinement of lambs has resulted in adequate growth (90 g/day or more) when fed maized crop residue plus supplements. Weanling kids fed the same ration have lower intake and gains of 20 to 40 g/day. Sorghum hay has been fed to lactating dairy goats. The fourth site, Morocco, has a Mediterranean climate with good rainfall in spring, prolonged drought in summer and fall, and cold limitation in winter (especially at higher elevations). Wheat stubble and other crop residues are under study for their nutritional contribution and supplementation requirements in summer, fall and winter. Also, studies are underway on productivity responses of native sheep in extensive or semi-intensive systems, as well as the prolific D'man breed in total confinement. The fifth site is Peru, where Andean highland areas are limited by cold year-round and extended drought for part of the year. Grazing systems for sheep and alpacas are under study at three Andean locations. At a coastal site, which receives sporadic rain (1 to 3 months, not every year), improved feeding systems for seminomadic herds of dual purpose goats are under study.