Physical and chemical limitations to the digestibility of tropical forages and strategies to overcome them | Limitaciones fisicas y quimicas de la digestabilidad de pastos tropicales y estrategias para aumentarla

Spanish; Castilian. sumarios (en, es)el alto contenido de fibra en forrajes tropicales y su reducida digestibilidad por los rumiantes, es uno de los mas grandes limitantes para la productividad animal en el tropico. en este articulo la discusion se centra en dos grandes areas. La primera tiene que ver con el consumo voluntario de rumiantes en pastoreo, factores que lo afectan y estrategias exitosas para incrementarlo. Debe reconocerse que, aunque de facil determinacion en animales estabulados, la estimacion de este parametro bajo condiciones de pastoreo ha sido tradicionalmente dificil e imprecisa. estrategias como la renovacion de praderas, el establecimiento de asociaciones graminea - leguminosa y la suplementacion estrategica, han sido utilizadas exitosamente para aumentar el consumo voluntario de rumiantes en pastoreo. La segunda area de discusion describe los factores que afectan la digestibilidad de la fibra en rumiantes y plantea estrategias para aumentar la degradabilidad de la fibra en el rumen. ambas areas estan muy relacionadas entre si, pues del adecuado entendimiento y optimizacion de ambos procesos, depende gran parte de la sostenibilidad economica y ambiental de la ganaderia del tropico.

English. The high fiber content in tropical forages, and its limited digestion by ruminants, is one of the greatest limitations to adequate animal productivity in the tropics. The discussion in this paper focuses in two areas: The first relates to voluntary intake by grazing ruminants, the factors that affect it and practical methods to increase intake in grazing or high-fiber consuming ruminants. For the value of discussion, it must be recognized that although assessment of voluntary intake of confined animals is not complicated, estimations of intake by grazing animals have been traditionally difficult and often imprecise. The implementation of pasture renovation strategies, the use of mixed (grass - legume) swards and of strategic supplementation, have often been reported as successful methods to increase voluntary intake by grazing ruminants. The second area of discussion relates to fiber digestibility in ruminants and includes comments on practical ways to increase rumen fiber degradability. Both areas are highly related with each other, and adequate understanding and management of factors that affect these two processes is needed to ensure the economic and environmental sustainability of cattle production in the tropics