Estimation of the forage potential of trees in silvopastoral systems of a dry tropical forest in Jalisco, Mexico

Dry tropical forests have a high diversity of local tree species with forage potential; these trees can be a strategic resource in the design of more sustainable livestock systems. The forage potential of sixteen selected tree species was evaluated in silvopastoral systems in Chamela, Jalisco, Mexico. Available biomass and nutritional quality of leaves and fruits consumed by cattle were estimated in the rainy and dry seasons. General and specific allometric models were generated in order to estimate potential biomass. Average available foliage was 0.96 ± 4.9 kg DM/tree, with a crude protein content of 148 ± 46 g/kg. Average biomass of fruits was 1.8 ± 3.7 kg DM/tree, with a crude protein content of 110 ± 54 g/kg. The best allometric models for foliage include canopy cover as a predictor, and canopy cover, height and base area in the case of fruits. Some of the evaluated species, such as Leucaena lanceolata, Guazuma ulmifolia, Ceasalpinia coriaria and Hura polyandra have outstanding forage potential, as they produce important amounts of foliage and fruits with a high nutritive value. They can therefore be recommended for use in livestock systems of the region to diversify grasslands and other agroforestry practices. Allometric models and nutritional analyses proved essential tools to estimate the potential contribution of trees to livestock feeding in the dry tropics, therefore assisting decision making in terms of the most appropriate species for silvopastoral systems.