GENETIC CONTRIBUTION OF MATERNAL PARENTS AND GRANDPARENTS TO ENGLISH THOROUGHBRED PROGENY PERFORMANCE

Genetic contributions of sires, dams and maternal grandsire and grandd am to progeny performance were evaluated in the German population of E nglish Thoroughbred. Performance was described by the maximum value of general handicap (GH). The statistical analysis of GH values of 102 s ires and their descendants (820 stallions and 899 mares) and maternal ancestors has led to a conclusion that genetic contributions of sires, dams and their parents are statistically significant. The genetic eff ects of dams and sires are of the greatest practical importance for se lection, the contribution of maternal parents is less important as the ir performance is only in weak correlation with the performance of gra ndchildren. The analysis confirmed an assortative scheme of mating in the population. The performance of offspring of selected parental pair s could be approximately predicted by means of linear regression funct ion, which is the sum of genetic effect of sire and multiples of perfo rmances (characterized by maximum value of GH) of dam and her parents. Prediction functions for male and female offspring had different regr ession coefficients.