EN
Results of reproduction of mares in the state horse studs for the last 10 years were analysed and compared with those obtained earlier. The analyses were based on yearly reports prepared by individual studs. A total of 2500 mares of Arabian, English, Low-Poland, Great-Poland, Silesian, cold-blood breed and Polish ponies were studied. In the examined period colting was 78%, a decreased of 0.9% comparied to the previous decade. A mean index of abortion and stillbirth was 10.5%, which was higher by about 3.1%. The number of abortions and stillbirths was the lowest (4.6%) in Arabian horses comparied to other breeds. A mean value of twin abortions was 2.1%. The lowest percentage of twins was noted in cold-blooded horses (0.4%) and in Arabian horses. Of all newborns, 8.7% (with a deviation of 7.2%) died or were killed up to the 6th month of life. A mean proportion of reared colts to mated mares during the last 10 years was 61.3% and this was lower than that at the earlier period of examinations. It is suggested that the lowered rate of horse reproduction resulted from worse economical conditions and a lack of preventive measures against equine arteritis, a disease which earlier was not common in Poland.