THE EFFECT OF STAGE OF GROWTH AND METHOD OF DRYING
FRESH HERBAGE ON CHEMICAL COMPOSITION OF THREE TROPICAL
HERBACEOUS FORAGE LEGUMES

THE EFFECT OF STAGE OF GROWTH AND METHOD OF DRYING
FRESH HERBAGE ON CHEMICAL COMPOSITION OF THREE TROPICAL
HERBACEOUS FORAGE LEGUMES

[EFECTO DE LA ETAPA DE CRECIMIENTO Y EL MÉTODO DE SECADO
SOBRE LA COMPOSICIÓN QUÍMICA DE TRES ESPECIES HERBACEAS
DE LEGUMINOSAS FORRAJERAS TROPICALES]

J. F. MUPANGWA

N. T. NGONGONI

H. HAMUDIKUWANDA

The objective of this study was to assess the effect of
stage of growth and method of drying fresh herbage on
the chemical composition of herbaceous forage
legumes namely Cassia rotundifolia (Cassia), Lablab
purpureus (Lablab) and Macroptilium atropurpureum
(Siratro). The interactions of legume species, drying
method and stage of growth influenced the crude
protein content and nitrogen degradation of the
legumes. Siratro maintained a greater protein content
ranging from 191 to 282 g/kg DM, at all stages of
growth and drying methods than either cassia or lablab
which had values ranging from, respectively, 173 to
246 and 162 to 254 g/kg DM, but were also different.
Drying the forages at 60 0C caused an increase in the
acid detergent insoluble nitrogen content of the
legumes. The neutral detergent fibre, acid detergent
fibre and lignin content of cassia and siratro harvested
at 8 or 14 weeks of growth were greater than in lablab.
While the protein content declines with fibre
increasing with advancing plant maturity, the legumes
tend to maintain a high CP content, which makes them
acceptable protein supplementary feeds to low quality
roughages. Among the three legumes, siratro showed a
higher sustained CP content followed by cassia, and
lablab was the least. To ensure high quality forage
more emphasis should be placed on drying methods
and harvest management as this affects the extent of
leaf loss from the forage legumes and hence the
quality of the final feed given to animals

Tropical and Subtropical Agroecosystems

2006