[Estimation of the heritability coefficient of stud fertility]

The breeding documentation of the English Thoroughbred horse breeding farm at Napajedla was analyzed to study some effects acting upon the fertility of studs and mares and the length of gravidity. The heritability of fertility is the subject of this report. The normality of the distribution of fertility was tested by processing 300 data on fertility at the given significance level sup / Fn(xi) - F(xi) / less than or equal to Dn(a). The value of the supreme D(300) = 0.108 is lower than the critical level for alpha 0.05. The estimation of fertility heritability coefficient indicates that h2 = 0.31; the heritability coefficient is at the boundary of low and medium heritability. The method of half-sib correlation was used for the calculation; 25% genetic similarity is involved in this case. The calculated value is an estimate characterizing the evaluated population. In view of the number of the observed studs, this value is regarded as informative. The problems under study are part of a wider range of problems concerning the evaluation of reproduction in the breeding of the English Thoroughbred Horse.