The objetive of this experiment was to obtain data from literature about diet composition for horses and to estimate the digestible energy and digestible protein contents by regression equations from chemical composition of these diets. Data were submitted to a correlation study among the content of nutrients in experimental diets and apparent digestibility coefficients, selecting the best correlation among DE, EAD, OMAD, CPAD and nutrients of diets. The values of EAD, OMAD and CPAD and digestible energy contents were fitted to simple and multiple linear regression equations in function of the nutrients contents fo the diets and in two classes of diets, roughage and mixed (roughage plus concentrate) diets. The best prediction equations for DE contents, in Mcal/kg DM, to all horses diets were: ED = - 0.104 + 0.0416 OMAD (r² = 0.85), DE = 5.0285 - 0.0144 OM - 0.0424 ADF (R² = 0.89) and DE = 3.7868 - 0.044 ADF (R² = 0.87). The most appropriate equation in roughage diets was: DE = 0.2273 + 0.0352 OMAD (r² = 0,70) and in mixed diets was: DE = - 0.3803 + 0.0459 OMAD (r² = 0,86). Prediction equation of apparent digestibility coefficient for crude protein in roughage diets was, CPAD (%) = 38.2446 + 1.7381 CP (r² = 0.53), appropriate to estimate the contents of digestible protein in alfalfa and coast-cross grass hays.
feedstuffs; digestible energy; equation prediction; digestible protein
