[Definition, incidence and causes of dystocia in horses - a review of the literature].

In horses, birth is classified as dystocia when the process of parturition threatens to inflict damage onto the mare or the foal, when assistance is required to complete the process of parturition, or when there are temporal deviations in the physiological duration of the first and/or second parturition stages. In this, the duration of the second stage is an important indicator in identifying dystocia, as this phase is easily discernible by the mare's behavior. Equine dystocia is classified as an emergency with life-threatening consequences for mare and foal. A large degree of variation has been found in the reported incidence of dystocia. Stud farm surveys reported dystocia in 2-13% of all births, regardless of breed. Fetal malpositioning of the limbs and neck during parturition is described as the most common cause of dystocia in horses. The species-specific length of limbs and neck is considered to be the reason for this finding.