더러브렛 경주마의 경주형질들에 대한 유전모수의 추정 = Estimations of Genetic Parameters for Racing Performance of Thoroughbred Horses

다국어 초록 (Multilingual Abstract)

The results obtained from a total of 18.926 rating records of 1,345 horses, from the Korea Racing Horse Association were as follows. 1. Square root transformations for total money (TM), average money (TM/S), curd percentage of first through second rank(% FSR) with a single record were more normally distributed than having natural logarithms. 2. Heridbility estimates for lest time average time. /TM/S, and / % FSR with entire records were 0.41, 0.53, 0.39, and 0.33, respectively. And heritabilities for the carne traits in 3-year-old horses generally showed highest. Taking account of genetic correlations among performance traits being always larger than those of phenotype, it was indicated that environmental factors were very important in racing taut, of horses. 3. the performance traits with repeated records were racing time, placing, and money in a race. Square root transformation of money in a race was more useful than that of natural logarithm, just like average money (TM/S). Considering the uniform distribution of placing records, transformation of placing records was implied to be important. 4. The estimates of heritibilities for racing time, money and placing in a race were 0.23, 0.10, arid 0.14, respectively. On the other hand, repeatabilities for the same traits were 0.34, 0.21, and 0.15, respectively. Taking in account racing time as being a good indicator of environmental effects, it should be considered as the most important trait in the genetic evaluation of racing horses. 5. PTAs` corelations between single records arid repeated records for racing traits were relatively high, and the same trend was found by age groups. Both genetic and phenotypic correlations for performance traits by age groups ranked highest in 4-year-old horses. This indicated that racing records for 4-year-old horses were very important for the genetic evaluation of racing horses.