This experiment was designed to adjust the biomathematical models of the phosphorus (P) flow between the physiologic or anatomical compartments of horses and to evaluate the P absorption and availability in horses, fed diets with different P levels from dicalcium phosphate. The model, deterministic and compartimental, was adapted of Aubert and Milhaud, in which the digestive tract and the bone and soft tissues represented the compartments in bi-directional flow with the blood. The informations on metabolism and kinetic of P in tissues obtained by the isotopic dilution technique were used. It was verified that the P levels from diets don't influence the changes of P between the blood and digestive tract; the P accretion in the bones and soft tissues tend to increase with the elevation of the levels of P, happening the inverse with the P re-sorption; the true absorption and P excreted in the feces and P balance in the bone and soft tissues in horse are positively related with the P dietary levels from dicalcium phosphate; the increase of supplemental P in diets containing dicalcium phosphate does not interfere in the P biological availability in horse.
foals; metabolism; phosphate; radio phosphorus
