Description Dimensions: 3.86 x 0.87 x 3.07 inch (W x D x H)Holsteiners are very talented jumpers. Just a few days after birth, the foals will jump joyfully and energetically over small obstacles. However, jumping training only begins in earnest at the age of two to three. By the age of five to six, the horsesâ muscles are sufficiently developed for them to carry a rider while jumping too.