Heart rate and salivary cortisol concentrations in foals at birth.

Abstract Heart rate (HR), HR variability (HRV) and salivary cortisol concentrations were determined in foals ( n  = 13) during the perinatal phase and until 5 months of age. In the fetus, HR decreased from 77 ± 3 beats/min at 120 min before birth to 60 ± 1 beats/min at 5 min before birth ( P  0.01). Within 30 min of birth, HR increased to 160 ± 9 beats/min ( P  0.01). Salivary cortisol concentrations immediately after birth were 11.9 ± 3.6 ng/mL and within 2 h increased to a maximum of 52.5 ± 12.3 ng/mL ( P  0.01). In conclusion, increases in HR and salivary cortisol concentrations in foals are not induced during parturition, but occur immediately after birth.