Circulating Levels of Total Cholesterol and Alkaline Phosphatase in Healthy Foals From Weaning to 18 months of Age Vary Significantly in Relation to Growth Stage

In view of the peculiar nutritional demands of the growing foal, the concentration of selected circulating parameters may display to mirror the metabolic activity of developing tissues across growth stages, following yields of mass and size, over time. This study aimed to evaluate the possible change of selected serum biochemical parameters in foals at different growth stages and to target these parameters as potential biomarkers of body development. Twelve Anglo-Arab spring-born foals were screened from weaning to 18 months of age. Live weight and gains were analyzed according to respective growth stage and correlated with biochemical parameters. Individual double whole blood samples were collected before and after weaning and when the foals were 12 and 18 months old. Body mass and wither heights (WH of yearlings) were concomitantly recorded. Foals appeared healthy throughout the trial and showed significantly different (P <.001) levels of total serum cholesterol (TC) and alkaline phosphatase (ALP) in relation to growth stages. Both those metabolites showed peaks in weanlings to progressively decrease in 18 months olds. On each sampling, ALP constantly displayed to set above the upper limit of the physiological range for the adult healthy horse. Results highlighted marked statistical significance across growth stages and point to ALP and TC as biomarkers of growth stage. These findings pave the way to the interpretation of circulating metabolites associated with growth stage and encourage further experiments to validate ALP and TC as potential biomarkers for body development assessment of foals.