Effect of plant growth stages on nutritional composition of promising Lucerne (Medicago sativa L.) genotypes

Nutritional composition of ten promising forage Lucerne genotypes was evaluated at pre-flowering, 50 per cent and post-flowering plant growth stages for dry matter, moisture, crude protein, cell wall constituents, in vitro dry matter and in vitro protein digestibility. Dry matter content at post-flowering stage was highest (23.27%) followed by 50 per cent (18.63%) and pre-flowering (16.91%) stages, respectively. Highest mean crude protein content was recorded at pre-flowering stage, followed by 50 per cent and post-flowering stages and the corresponding values were 20.82, 19.81 and 18.06%, respectively. In vitro dry matter digestibility at pre-flowering stage was maximum (66.83%) followed by 50 per cent flowering with (64.76%) and post-flowering (60.78%) stages. In vitro protein digestibility at 50 per cent flowering stage was also maximum (85.97%) followed by the post-flowering (82.61%) and pre-flowering (80.11%) stages. Amongst the cuttings of forage lucerne genotypes at different plant growth stages, the cell wall constituents, viz., neutral detergent fibre, acid detergent fibre, hemi-cellulose and acid detergent lignin were the lowest at pre-flowering stage and thereafter increased continuously with the advancement of growth stage.