These results confirm that the quality of the two studied
tall fescue cultivars is not steady through the vegetative stage. Leaf blade digestibility decreases with leaf age and with
the increase in leaf length among successive generations
of leaves that form a regrowth cycle. The quality loss of the
leaf blades is due to the decrease in NDFD. The NDF content only increases during the process of leaf senescence,
but remains stable until the end of leaf life cycle. Cultivars
show similar quality at the same ontogenetic stage. However, the cultivar Advance shows shorter LLS (490 vs 632
GDD), which means that ages faster and therefore loses
digestibility at a higher rate. At an average temperature of
20 °C the leaf blades of the Advance cultivar would complete their life cycle, or biomass accumulation cycle, 9 days
before than El Palenque Plus. Therefore, it requires more
frequent defoliations in order to maintain a quality comparable to the one of the traditional cultivar.