Original ArticleTriglyceride concentrations in neonatal foals: Serial measurement and effects of age and illness

•Serum triglyceride concentrations varied with age during the neonatal period and differed from those in adult horses.•Triglycerides were lowest immediately postpartum, peaked within one week of age, and then declined.•Nonsurviving sick foals had higher serum triglyceride concentrations than surviving foals.

Few studies have evaluated the effects of age and illness on serum triglyceride concentrations in neonatal foals. The objectives of this study were to evaluate triglyceride concentrations in neonatal foals and their dams through serial measurement immediately postpartum and at 1-2 days and 10-12 days of age, as well as to measure them in sick foals.Serially measured serum triglycerides in seven healthy foals varied with age. Median (range) triglyceride concentrations were 28 mg/dL (12-50 mg/dL), 89 mg/dL (51-264 mg/dL), and 60 mg/dL (28-135 mg/dL) immediately postpartum, at 1-2 days of age, and 10-12 days of age, respectively (P < 0.001). Triglyceride concentrations varied hourly by up to 117 mg/dL in individual foals. The dams had lower triglycerides (median, 20 mg/dL; range, 12-49 mg/dL) than the foals, once foals were >24 h old. Sick foals <24 h old had lower triglycerides than sick foals aged 1-7 days (median, 41 mg/dL [range, 16-116]; median, 110 mg/dL [range, 24-379 mg/dL]; P < 0.001). Age and triglyceride concentration showed a non-linear association independent of foal health status (P = 0.01). Sick foals with positive bacterial cultures had higher triglycerides than those with negative cultures (median, 111 mg/dL [range, 10-379 mg/dL] and median 53 mg/dL [range, 17-271 mg/dL], respectively; P = 0.033). Nonsurvivors had higher triglycerides than survivors (median, 116 mg/dL [range, 41-379 mg/dL] and median, 55 mg/dL [range, 10-311 mg/dL], respectively; P = 0.04). In conclusion, triglycerides were highest in healthy neonatal foals aged 1-2 days, and in nonsurviving sick foals and those with positive bacterial cultures. Age was associated with triglyceride concentration regardless of health status.