The Byelorussian has a high fertility and longevity. Mares have often remained fertile to the age of 26. Two types, the large and the medium, are distinguished within the breed. There are 6 lines and 4 mare families. The leading breeding centers are Zarechye stud and the stud on Pobeda state farm in Byelorussian.
Improvement is by pure breeding.
Two volumes of the studbook have been published, listing 135 stallions and 616 brood mares. A new line is currently being tested. As of 1 January 1980, the Byelorussian Harness breed numbered 93,040, including 27,560 purebreds.