Potencial productivo de siete híbridos de Urochloa bajo sol y sombra arbórea

Background: Ruminant diets in tropical areas are primarily based on native grasses. However, in some regions, low rainfall, high temperatures, and certain soil physicochemical characteristics interfere with pasture production, affecting yield, nutrient quality, and digestibility. In recent years, hybrid grasses have led to improved forage yields of high-quality nutrients year-round, improving pasture utilization for livestock production. Objective: To evaluate the productive potential of seven hybrids of the genus Urochloa established under sun and tree shade conditions at three cutting ages and three climatic conditions. Methodology: The study was conducted at the Centro de Enseñanza, Investigación y Extensión en Ganadería Tropical (CEIEGT-Tlapacoyan, Veracruz), where the following grasses were evaluated: Cobra, Cayman, Mulato II, Camello, GP 1435, GP 1467, and Mestizo Blend during the rainy, northern, and dry seasons. Cutoff frequency was measured 28, 35, and 42 days post-sowing. Dry matter (DM) production and its nutritional quality were estimated. Results: The highest dry weight production per clump was obtained under sunny conditions, with a 36% lower dry weight in shade. Production under both conditions increased at 42 days, with a greater increase in leaf production under shade. Independently of the condition, the highest production in the dry season was obtained from Cobra, in the rainy season from Mestizo Blend, and in the north, production was similar in all species except for GP 1467, where it was lower. For the season by age interaction, an increase in production was observed as the days passed, with a 50% higher production at 42 days compared to 28 days; however, at 35 and 42 days, no significant difference was observed (P>0.05). Implications:  This study contributes to a better understanding of the development of hybrid grasses and is considered useful for improving the use of tree shade systems. Conclusions: It is concluded that dry matter production in Urochloa hybrids is influenced by light conditions (sun/shade), cutting age, and season. It is noteworthy that in this study, shade reduces production, and that, in general, production increases with age. These results highlight the importance of considering the environment and cutting management to optimize forage yield.