THE NUTRITIONAL-VALUE OF LUCERNE (MEDICAGO-SATIVA L) IN DIFFERENT DEVELOPMENTAL STAGES

Changes in nutritional values with plant development were studied in lucerne (Medicago saliva L. cv. Hairy peruvian) at Kulumsa in Ethiopia during four growing seasons in 1985-87. As estimated by linear regression equations the content of crude protein (CP) and the in vitro organic matter digestibility (IVOMD) declined at the rates of 0.12 and 0.14 percentage units per day, respectively, due to advance in plant development during the four growing seasons. Neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin increased at the rates of 0.16, 0.06 and 0.03 percentage units per day, respectively. NDF was more negatively correlated to IVOMD than ADF and lignin. The contents of total ash, K, P and Mg declined significantly with advancing plant development, but no consistent trends were observed for Ca and Na. At advanced stages of development, contents of P and Mg dropped below the required critical levels. Because of high losses of leaves, delayed harvesting of lucerne beyond the bud stage would result in lower total yield of nutrients.