When the birth of a foal proceeds normally, it is not stressful for its mother. A mare delays parturition until her environment is peaceful and safe. Indeed, most foals are born at night.
The research on stress in foaling mares was conducted at the school of veterinary medicine at the University of Vienna. The birth of 17 foals was observed, and the blood of the mares was examined for the presence of stress hormones. Electrocardiogram recordings were also made. Most of the births lasted ten to twenty minutes. During foaling, it turned out, the mares were strongly influenced by their parasympathetic nervous system, which induces rest and relaxation. The mares’ heart rate did not increase during foaling, and stress hormone levels remained low. When the foal is born, the mare is calm and relaxed.