A total of 1834 lactation records of Holstein cows were used for studying the
random effects of sire and cow within sire and the fixed effects of year of calving,
month of calving and parity on 305 day milk yield (305-dMy), lactation period (LP), dry
period (DP), days open (DO), number of service per conception (NSPC) and calving
interval (CI). Least squares analysis of variance showed significant effect of sire on 305-
dMY only (P productive and reproductive traits studied. The effect of fixed factors were mostly
significant (P<0.05) & (P 11.31±O.5 kg/d (P-10.93±O.83 kg/d (P that reduction in dry period is considered if it is a desirable goal for dairymen. Heritability estimates were moderate for 305-dMY and LP (0.33 and 0.19
respectively) and extremelly low for DP, DO, CI and NSPC (0.02.0.01.0.02 and
0.01), respectively. Most estimates of genetic correlation were nearly similar to the
corresponding estimates of phenotypiC correlation in values having the same
direction.