Retinol serum concentrations were analyzed from 16 pregnant mares raised in farms of two different regions of Minas Gerais state, Brazil (Vale do Rio Doce and Sul de Minas). The animals were maintained on pasture with free access to mineral supplement without grain concentrate supplementation. Blood samples were collected monthly from May to November 2002, aiming to verify the need of vitamin A supplementation during the dry season. The concentration of beta-carotene from pasture samples was also correlated with blood plasma concentration to verify the utilization of hepatic stock of vitamin A. High performance liquid chromatography (HPLC) was used to determine vitamin A and beta-carotene concentrations. The used statistics was the split plot design and the results were compared by Duncan test. The Pearson correlation between the serum concentration of retinol and beta-carotene from pasture was estimated. The results demonstrated that the supplementation of pregnant mares in farms of the studied regions was not necessary during the dry season and that no significant correlation between the serum concentration of retinol and beta-carotene from pasture was observed.
equine; beta-carotene; vitamin A; forages; nutrition; retinol
