Evaluation of Tropical Herbaceous Legumes for Drought Resistance in Myanmar

Animal nutrition systems in the tropical and subtropical countries utilize a wide range of feedstuffs, mainly the crops and agricultural by-products, grasses, legumes, trees and shrubs. During the dry season, the crude protein concentration in the native grasses can drop below 3% crude protein (Atta-Krah and Reynolds, 1989). Fodder tree is not sufficient and is of low quality in Myanmar (Myo and Aye, 2007). Shrubs represent an enormous potential source of protein for ruminants in the tropics (Devendra, 1992). Browses are rich in nitrogen and minerals which are low in other conventional feeds of tropical regions. Herbaceous legume species play an important role in feeding ruminants worldwide. Herbaceous forage legume have been identified as potential protein supplements for ruminants since they contain high crude protein, minerals and vitamins needed for the growth of ruminal microbes (Norton and Poppi,1995). Herbaceous legumes can be grown as a relay within cereal crops or as a rotation with cereals. Herbaceous legumes can access ‎atmospheric ‎N‎ (‘fixation’)‎ through‎ bacterial‎ activity‎ in‎ root ‎nodules.‎ The‎ ‘fixed’ ‎N‎ becomes‎ available ‎to‎ the‎ legume and subsequent cereal crops. Herbaceous legumes are best planted from seed (Nulik et al., 2013). The aim of using herbaceous legumes in cropping systems is to increase animal productivity, particularly live weight gain in animals being prepared for market. Herbaceous legumes may be fed directly to animals as fresh material in the late wet and early dry seasons, with browse or tree legumes retained for later dry season feeding, or stored as hay and fed in the late dry or early wet seasons when the availability and quality of local feed is lower (Nulik et al., 2013). Legume based pastures give high individual animal performance for growth, fattening, reproduction and wool growth. Cattle live weight gain has been related positively to the proportion of legume in the sward (Mureithi et al., 1995). As pastures become mature, they are characterized by high content of fibre with a higher grade of lignifications and low protein content (Enoh et al., 2005). In Myanmar there is only 0.35% cultivated pasture area to that of cultivated acreages. The improvement and development of pasture is a necessity for Myanmar (Myo and Aye, 2007). For that reason it is needed to evaluate the yield herbaceous legumes for the potential use for ruminants in Myanmar

Selection of Suitable Varieties of Grasses for Myanmar

The basal feed resources for ruminants available in most developing countries in the tropics are crop residues, pasture from infertile land, for example communal land, or agro-industrial by-products. These are low in protein and of low digestibility. A major problem facing livestock producers in tropical areas is proper nutrition for their animals during the dry season when pastures, cereal residues and maize stover are limiting in nutritional quality. The researchers in Myanmar have tried to improve the nutritive value of fibrous agricultural residues. Aung Aung et al. (2006) supplemented the sesame and chickpea husk to bulls fed on urea-treated rice straw. One way of improving the utilisation of such crop residues is by proper supplementation with leguminous forages (Poppi and McLennan 1995). In most regions of Myanmar, the green forage is available during the rainfall and become shortage during dry season. Therefore, feedstuff for ruminant animals mainly has to depend upon the availability of agricultural by-products. Almost more than half of the livestock population of Myanmar is inhabited in dry zone and thus, to overcome the scarcity of the feedstuff during summer, the irrigation system was introduced in these areas for the development of agriculture. A simple and effective way to increase livestock production is to grow improved pastures. Throughout Myanmar, extensive areas of idle land could grow excellent pasture. At present, most of the “pastures” consist of low rank, poor quality grasses and a limited range of edible shrubs. During prolonged dry periods, grazing animals subsist on dry mature roughage of poor quality (Myo Kywe and Tin Mg Aye, 2007). Grass species, which can rapidly grow after the rain also having drought tolerance, would be very useful in the production system. There is still little information on the use of forage in Myanmar. It is needed to select the grass species which have drought resistance in Myanmar and thus this experiment was conducted to evaluate a range of introduced tropical grasses in the central dry zone of Myanmar