Estimation of red clover (Trifolium pratense L.) forage quality parameters dependingon the variety, cut and growing year

A field trial was conducted to determine the nutritive value of eight Slovak and Czech red clover varieties and to quantify the effects of variety, cut and year on red clover forage quality. The differences between forage quality of the evaluated red clover varieties were significant for protein supplied when energy is limited in the rumen (PDIE), intestinal digestibility of rumen non-degraded protein (dsi), net energy values and ash content (P < 0.01). The achieved results show that the surpassing forage quality was given by diploid Viglana variety with high protein and energy values. The forage of tetraploid varieties Javorina and Dolina was outstanding in protein content, but had the lowest energy values. The nutritive value was significantly affected by cut. The first cut provided forage with a significantly lower (P < 0.01) crude protein (CP) content, CP digestibility, degradability of CP (degNL), protein supplied when nitrogen is limited in rumen (PDIN), PDIE and with a significantly higher crude fibre content and energy values (P < 0.01). The differences between varieties were more pronounced in the second and in the third cut. Significantly higher (P < 0.01) PDIE, PDIN, degNL, net energy values and ash contents were found in the first production year.