ANALYSIS OF SELECTION PROGRAM IN MEAT POU LTRY BY MEANS OF ANIMAL-MODEL

To estimate breeding value, data on the performance of two strains and six generations of hens of meat type were used for the commercial cha racteristics egg production, chick weight at 42 days of age and age at sex maturity. A total of 19,928 birds were analyzed within strain A w hile it was 20,871 individuals within strain B. All genetical relation ships were used for the calculation of breeding value estimates in ind ividual birds. Estimates were calculated separately for each trait. Da ta were processed using an animal model (AM). Average breeding values and correlations between breeding values for the particular traits wer e determined for the separate generations. In strain A breeding values between six generations for egg production ranged from -0.0435 to 6.1 218 eggs, for chick weight from -3.716 to 16.229 g. In the case of sex maturity, breeding values were calculated in the last three generatio ns only, with the range from 0.0805 to 0.2482. The calculated values i n strain B for egg production ranged from -0.0248 to 8.301 eggs, for c hick weight from -0.784 to 131.500 g and for sex maturity (calculated for three generations only) from 0.0757 to 0.0001 days. Average values are very close to zero. Differences between the successive generation s show a desirable developmental trend. Total variabilities of individ ual breeding values (deviations from the mean) for the commercial trai ts ranged in strain A for egg production from -28.38 to 21.78 eggs, fo r chick weight from -280.6 to 366.3 g and for sex maturity from -5.67 to 12.49 days. In strain B, individual breeding values ranged for egg production from -21.15 to 19.83, for chick weight from -321.3 to 381.3 g and for sex maturity from -5.23 to 7.21 days. The variance size of the breeding value range is significant for each trait. An expected ne gative relation between egg production and sex maturity in both strain s is highly significant (r = -0.25 and -0.31). Relationships of chick weight to egg production and to sex maturity are different in the stra ins. The relatively large range of breeding values and their correlati ons for the particular commercial traits as calculated indicates a lar ge space for effective selection and a necessity of careful selection of individual birds for further breeding with AM method application.