EN
Race performance of 428 three years old halfbred horses racing on the track between 1984-1987 /on the basis of Race Track Bulletin and Stud Books: Km T. I-IV, Kwlkp T. I-IV, Kśl T. III-IV /were analysed. The horse breed and percentage of thoroughbred blood and purebred Arabians in their pedigree were studied. Individual Coefficient of Success /IWP/ as a comparison rate was used. We were also interested in the "gentle" halfbred horses. We payed special attention to the horses with IWP> 2,0. Results were statisticly analysed, then. Horses belonged to 6 breed groups: Little Poland Horses, Great Poland Horses, Angloarabians, Silesians, Hannovers, "Gentle" Halfbreds. The Anglo- arabians had the hifhest average IWP - 2,14j the next ones were: Little Poland Horses - 1,179, Hannover Horses - 0,97, "Gentle" Halfbreds - 0,85, Great Poland Horses - 0,82 and Silesians onses - 0,73. Average IWP /taking under consideration the percenta e of thoroughbred blood in pedigree/ is shown as following: 1,93 for horses with 75% and more of thoroughbred blood, 1,16 for horses with.≤ 50% and ≤ 75% of this blood, 0,73 for horses with 50% and 0,77 for horses with <50% of throughbred blood.