BODY-WEIGHT AT BIRTH OF DAMS AND THEIR DAUGHTERS AS A BASE OF HEIFERSSELECTION UNDER HUNGARIAN CONDITIONS .2. IMPROVEMENT OF DAYS OPEN ANDNUMBER OF SERVICE PER CONCEPTION

Days open (DO), number of service per conception (NOS), birth weight o f dams and their heifers (EW1, BW2) were used as variables in heifers selection subindices. A 3225 complete lactation record of 812 cows wer e involved in construction of dam-heifer selection subindices (I-1: al l the four traits were included, I-2: only BW1, BW2 and DO, and I-3. o nly BW1, BW2 and NOS). Cows were daughters of 185 sires. Number of cow ; per sire ranged from 4 to 5. Variance and covariance estimates as we ll as fixed random effects were estimated by mixed model of Maximum Li kelihood Procedures. The selection subindices and traits were estimate d according to their effect on genetic gain Relative efficiency of I2 and I3 to I1 were 84.18% and 84.27% in selection for DO, respectively and 163.84% and 77.84% in selection for NOS in the same order. The bes t subindices for DO and NOS improvement were I1 and I2. The expected g enetic gain in NOS and DO per generation were low and ranged between 0 .8993 to 0.9563 services and 7.81 to 9.28 days respectively.