[Characteristics of bull semen]

Studied were comparatively some morphologic, biochemical, and biological methods employed to characterize the biologic value of bull's semen. Particular attention was paid to the objective methods of evaluation. Reflected is the experience gained in this country as well as the author's personal experience in characterizing the ejaculates and storing 24-72 H semen at 0-4 degrees C and continuous storing at ultralow temperatures. Given are also the theoretic achievements on the problem, and a stress is laid on the applicability of the methods for evaluating the semen in the artificial insemination practice with cows.