Energy and mineral metabolism of peripartum mares and foals of the Quarter Horse breed

Background Several studies have demonstrated variations in peripartum blood biochemical analytes used to monitor the health status of mares and their foals of different breeds. Objectives We aimed to characterize the physiologic changes of peripartum energy and mineral metabolism in healthy Quarter Horse mares and their neonatal foals. Methods Blood samples were initially collected from 17 mares on days 60 and 30 prepartum, and from mares and their foals on the day of parturition (after colostrum ingestion), and on days 15, 30, and 60 postpartum. The serum concentrations of calcium, phosphorus, magnesium, total cholesterol (T-Cho), triglyceride, beta-hydroxybutyrate (BHBA), and nonesterified fatty acids (NEFA) were measured using commercial kits. Statistical differences were analyzed using one-way ANOVA followed by Tukey's test (parametric variables) or the Kruskal-Wallis test followed by Dunn's multiple comparison test (nonparametric variables). Results Fourteen of 17 healthy Quarter Horse mares and their neonatal foals remained in the study until termination. Serum BHBA, T-Cho, and calcium concentrations in mares showed significant differences during the observation period. Serum BHBA concentrations increased from 60 days prepartum to 60 days postpartum. Postpartum serum T-Cho and calcium concentrations significantly decreased until day-30 postpartum. In the foals, NEFA, T-Cho, calcium, and magnesium concentrations significantly differed between sampling times. In the foals, serum NEFA concentrations decreased from parturition until day-60 postpartum, while serum T-Cho, calcium, and magnesium concentrations were lowest at day-30 postpartum. Conclusions The temporal changes observed in the blood biochemical analytes of this study could be used to improve the clinical evaluation of periparturient mare and neonatal foal Quarter Horses.