CONSTRUCTION OF 2-STAGE SELECTION INDEX F OR BULLS OF THE CZECH PIED BREED

For the purposes of a breeding program of the Czech Pied cattle weight coefficients b were calculated and selection indexes were made up for two-stage selection of bulls. The characteristics subjected to milk a nd meat recording were included in selection index. They are shown wit h sources of information and values of the accuracy of breeding value estimate in Tab. I. Tab. III shows the characteristics involved in the aggregate genotype and economic weights. The algorithm after Cunningh am (1975) was taken as a basis for the calculation of weight coefficie nts for the 1st and 2nd stage of selection. Tab. IV shows the calculat ed weight coefficients for the 1st and 2nd stage of selection. Their v alue indicates that in the 1st stage the negative weight of fat conten t in milk is assigned in the mothers of tested bulls. In the 2nd stage the negative weight of fat content in milk, dystocia at calving of fe male (in half-sisters and daughters of investigated bulls), calving in terval in half-sisters and number of inseminations with the semen of t he investigated bull per conception of heifers and cows was assigned. The positive weight was determined in the latter stage among other val ues for return interval, dystocia at calving of male (in the heifers a nd cows inseminated with the semen of the investigated bull) and masti tis. The ensuing potential positive or negative selections can be elim inated by introduction of restrictions for the above traits. The resul ts are influenced by management economics, and in the milk components by the system of their pricing. It follows from the correlations betwe en the indexes and aggregate genotype determined for the 1st stage of selection (r = 0.53) and the 2nd stage of selection (r = 0.73) that se lection in the second stage is more accurate.