Trakehner mare A Trakehener mare can only have a foal with a Trakehner, Arab or Thoroughbred stallion. A Trakehener mare can only have a foal with a Trakehner, Arab or Thoroughbred stallion. This rule is intended to preserve the breeds elegant build and spirited character. Trakehners originated in the East Prussian town of Trakehnen, near Kaliningrad in Russia. Fun fact Trakehners are believed to be Germanys oldest horse breed.