Nutritive value of some grasses and leguminous tree leaves of the Central region of Africa

Variation in the nutritive value of three common pasture grasses: Brachiaria ruziziensis, Pennisetum purpureum, Trypsacum laxum and leaves of two leguminous trees: Leucaena leucocephala and Calliandra calothyrsus, were determined throughout a calendar year. Sampling at each foliage was completed monthly between November 2001 and October 2002 followed by analysis for their chemical components. The crude protein (CP) level in the tree leaves was higher than that in the grasses throughout the year while the reverse was true for NDFom and ADFom. There was an increase in the CP level during the rainy season for all forages, and this increase was higher (P<0.01) in B. ruziziensis, P. purpureum, L. leucocephala and C. calothyrsus (P<0.05), respectively, relative to the dry season samples. Lipid levels were higher (P<0.05) in B. ruziziensis and C. calothyrsus during the rainy season. Sulfuric acid lignin (sa) was higher (P<0.01) in B. ruziziensis and L. leucocephala during the dry season. Brachiaria had the highest level of P irrespective of season. Seasonal variations in the levels of the nutrients in these foliages suggest that, throughout the year, different amounts of leguminous tree leaves would be needed to supplement diets of ruminants whose main feed comes from grazing natural pastures, as is the case in the Central African region. This will help to ameliorate the overall productive and reproductive performance of ruminants in the region.