Forage yield and digestibility of Urochloa spp. cultivars at three regrowth ages in the rainy and dry seasons in Ecuador

Abstract

The humid tropics of Ecuador is a potential livestock production area. Urochloa spp. cultivars are a forage option in this region. Environmental and management conditions determine forage yield and nutritional value and should be researched prior to establishing new forage species. An evaluation was done of total dry matter yield (TDM; t ha-1), morphological components proportions (%; leaf, stem, dead material and inflorescence) and in situ dry matter digestibility (DMD; g kg-1)) in five Urochloa cultivars (Mulato II, Marandú, Xaraés, Piatá and Señal [control]) and at three regrowth ages (4, 6 and 8 wk) during the rainy and dry seasons. A completely randomized block design in a split plot arrangement was used to analyze the data by season. During the rainy season, TDM did not differ (P>0.05) between cultivars. In the dry season, Marandú had a lower yield than Xaraés (0.92 vs 1.21 t ha-1). Morphological component proportions differed between cultivars (P<0.05), although the leaves contributed the most overall to yield. From four to eight weeks, DMD decreased from 64 to 56 % in the rainy season and from 60 to 56 % in the dry season. The evaluated cultivars exhibited acceptable TDM yields (2.6 t ha-1 in rainy season, 1.0 t ha-1 in dry season) and DMD (602 g kg-1 in rainy season, 574 g kg-1 in dry season). They are adequate forage alternatives for livestock in the humid tropics of Ecuador.