الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 183 |  |  |
| | | from | 183 | | |
Abstract
In the present study, 1809 records of Russian Black Pied cows were used. Data were collected over a period of sixteen years (from 1968 to 1983). The main objectives of this study were to estimate genetic and non-genetic factors affecting productive and reproductive traits in dairy cattle. Genetic and phenotypic parameters for these traits were also determined.Five models of statistical analysis, by using Harvey program, were used for analyzing factors affecting productive traits (TMY, 305DMY, FCM, AMY, FY, FP, LP and DP) and reproductive traits (CI , DO and AFC). from the results it could be concluded that:**The significant sire effect on productive and reproductive traits indicate to the possibility of genetic improvement through sire selection.**The significant effect of fixed effects on the studied traits explain the importance of data correction for these factors before making selection between cows.**Because of the significant effects of parity on most productive traits studied, more attention should be given to cows in the first parity in order to improve the productivity of the cows.** The moderate values of heritability estimates of most of studied traits indicate to the possibility of increasing the productivity of the cows using genetic improvement.**The high genetic correlation between productive traits indicate that the genetic improvement in one of these traits will lead to improvement in other traits.**The antagonism between TMY and FP must be taken into consideration when making selection indexes using multi-trait indexes.