Submitted to: Animal Feed Science And Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/30/2000
Publication Date: N/A
Citation: Interpretive Summary: Sheep in North Sumatra, Indonesia, are used by farmers as a source of protein and as a living bank. In the later case, sheep are sold to provide added income for special social needs as schooling for children or repair or expansion of housing. Consequently, sheep are retained in confinement because of lack of fencing throughout the region and the high incidence of theft. A major cost in raising lambs is supplemental protein because the tropical grasses fed (cut and carry) are generally inadequate to meet the animal needs. Legume trees grow in great abundance throughout the region and can be cut and carried and fed in confinement. This study showed that two legume trees, Paraserianthes falcataria and Gliricidia sepium, were readily eaten by lambs and gave dry matter intake of 3.2 and 2.5% of body weight, respectively. Calliandra calothyrsus, with highest tannin concentrations, was consumed at only 2% of body weight. A herbaceous dicot, ,Asystasia intrusa, which grows very aggressively under low light of rubber plantations, was consumed at 2.5% of body weight. In application all three legume trees would be fed as a crude protein supplement to tropical grasses and all three have this potential. Asystasia intrusa shows potential as a sole diet, but its aggressive growth habit may permit it to become a weed in rubber plantations if not properly managed.
Technical Abstract: The tropical tree legumes Paraserianthes falcataria, Gliricidia sepium, and Calliandra calothyrsus were fed to ram lambs to evaluate their potential as feeds. Dry matter intake, digestibility of dry matter, neutral detergent fiber and nitrogen, and digestible energy content were determined through a digestion study. The herbaceous dicot Asystasia intrusa was included as an underutilized source of nitrogen and Brachiaria brizantha was included as standard tropical (C4) grass. Of the tree legumes, C. calothyrsus had the highest level of soluble phenolics (SPHE), averaging 38% of dry matter, and soluble proanthocyanidins (SPRO), averaging 13.7 absorbance units per gram (AU g 1) of dry matter. P. falcataria was intermediate, averaging 15% SPHE and 4.8 AU g 1 SPRO, with G. sepium the lowest, with 5% SPHE and 0.4 AU g 1 SPRO. Dry matter intake (percent of body weight) was lowest for C. calothyrsus fed lambs, averaging 2.0%, compared with 3.2% for P. falcataria aand 2.5% for G. sepium. Intakes were similar for A. intrusa and B. brizantha, averaging 2.6%. C. calothyrsus also had the lowest dry matter digestibility, averaging 55%, compared with 61% for P. falcataria and 63% for G. sepium, which were similar. Highest dry matter digestibility was obtained for A. intrusa, averaging 72%, and B. brizantha, averaging 65%. Forages had similar rank for neutral detergent fiber digestibility. Proanthocyanidins in the tree legumes may have bound with cell wall carbohydrates, resulting in a reduction in dry matter and NDF digestibilities.