Caracterizações bromatológicas e energéticas de seis espécies de árvores com potencial forrageiro na região tropical seca de Sinaloa, México.

The objective of this research was to identify the tree species used in feeding cattle, as well as their density and nutritional value in Sinaloa, Mexico. The study was carried out through monthly samplings and a survey to producers. The variables evaluated were Dry Matter (DM), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Cellular Content (CC), Potential Dry Matter intake (PDMI), Digestible Energy (DE), Net Energy for maintenance (NEm), Net Energy forgain (NEg), Net Energy for lactation (NEl), Total Digestible Nutrients (TDN) and Growing Degree Days (GDD). The results showed the following order of tree consumption preference by cattle: (1) 'Lysiloma divaricatum', (2) 'Acacia farnesiana', (3) 'Ebenopsis ebony', (4) 'Tabebuia rosea', (5) 'Guazuma ulmifolia' and (6) 'Chloroleucon mangense' Jacq. The NDF content was the highest in 'Tabebuia rosea' (54.4%) as well as in ADF (42.8%) and 'Ebenopsis ebano' was the lowest (19.3%). The highest content was observed in 'Ebenopsis ebano' (4.9%) and 'Acacia farnesiana' (3.7%). The highest NEl content was observed in 'Tabebuia rosea' (1.99 Mcal/kg DM), and the lowest in 'Guazuma ulmifolia' (1.26 Mcal/kg DM). 'Ebenopsis ebano' showed, the highest content was observed in NEl (1.86 Mcal/kg DM) and the lowest was observed in 'Tabebuia rosea' (1.22 Mcal/kg DM). A significant difference (P<0.05) was observed in the accumulation of average GDD per day by forage species. 'Acacia farnesiana' is the forage tree with the highest consumption by cattle and the one that presented the highest density in the sampled area. 'Chloroleucon mangense' is the second most important species, despite its low density in the study area. GDD were higher in the summer season, while the lowest amount occurred in autumn, which was reflected in differences in the quality and quantity of the forage.