Efecto de la edad de rebrote y clima en la calidad nutritiva de Neonotonia wightii cv Longicauda en Pataza, Ecuador

Neonotonia wightii cv. Longicauda is a tropical legume that supports sustainable ruminant production in humid ecosystems. The study evaluated regrowth age (30, 60, and 90 days) and seasonal rainfall patterns affecting its nutritional quality in Pastaza, Ecuador. Plots were harvested during the rainy (December–February) and low-rainfall periods (July–September) using a randomized complete block design with six replicates. Crude protein declined sharply with maturity, decreasing from 25.0 to 14.5% in the rainy period and from 23.5 to 16.2% in the dry period between 30 and 90 days. This reduction reflected protein dilution as structural carbohydrates accumulated during progressive lignification. Fiber fractions (NDF, ADF, lignin) increased correspondingly, reducing in vitro dry matter digestibility from 75.0 to 59.7% in the rainy period and from 70.6 to 65.3% in the dry period. Soluble sugars (glucose, fructose, sucrose) decreased by 70–85% with advancing maturity. Secondary metabolites, particularly total tannins and phenols, accumulated markedly under low-rainfall conditions and at later growth stages, likely as a plant defense response to water stress. Metabolizable energy followed the same declining pattern with maturity but remained consistently higher during the rainy period. Remarkably, fermentation kinetics parameters (asymptotic gas volume, rate, lag time) remained stable across all treatments, indicating consistent ruminal fermentability despite compositional changes. The results showed that harvest timing determines forage quality, younger regrowth better preserves protein content and digestibility, especially during drought conditions. Integrating seasonal rainfall patterns into cutting management optimizes nutritional value and strengthens resilient livestock production in tropical environments.