الفهرس 
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Abstract
Data used in the present investigation were collected from the history sets of three genotype groups of cows (Friesian cows maintained at Sakha and El-Karada experimental farms at Kafrelsheikh governorate), (Baladi cows kept at El-Serow experimental farm at Damietta governorate and El-Gemeza experimental farm at Gharbia governorate) and (the crossing of Friesian × Baladi belonged to El-Gemeza experimental farm at Gharbia governorate).
A total of 5135, 492 and 1381 normal lactation records of Friesian, Baladi and their cross cows, respectively, were used in the present study over the years from 1979 to 2010.
• Harvey program statistic (Harvey, 1990) was used to determine the fixed effects to be contained in the analytical model.
• Data were analyzed by Multiple Traits Derivative Free Restricted Maximum Likelihood (MTDFREML) according to Boldman et al., (1995) to estimate variance components and heritability.
• Best linear unbiased prediction (BLUP) of evaluating breeding values (EBV) was calculated by back solution using the MTDFREML program for all animals in the pedigree file for multi-traits analysis.
The objectives of the present study were to:
1- Test the significance of the non-genetic factors influencing productive (305-DMY, kg, LP, d) and reproductive traits (CI, DO, d) for the three genotype groups (Friesian, Baladi and cross cows).
2- Estimate genetic and phenotypic parameters of productive and reproductive traits for the three genotype groups.
3- Evaluate cow, sire and dam breeding values for the above traits.
The results obtained from the present study can be summarized as follows:
1- Means and standard deviation (SD) of 305-DMY, LP, CI and DO for Friesian cows were 3465±1077 kg, 302±98 d, 445±102 d, and 175±103 d, respectively; for Baladi cows were 1778±698 kg, 166±59d, 436±95 d, and 149±87 d, respectively and for Cross cows were 2996±908 kg, 324±100 d, 477±118 d and 190±84 d, respectively.
2- Year of calving and genotype groups had a highly significant effect on 305-DMY, LP, CI and DO (P<0.01). Moreover, season of calving had a highly significant effect on 305-DMY, significant effects on LP (P<0.05), but had non-significant effects on CI and DO. However, parity had a highly significant effect on 305-DMY, CI and DO, but had a significant effect on LP.
3- Heritability estimates for all traits were 0.24, 0.22, 0.16 and 0.17, respectively, for Friesian cows; 0.26, 0.28, 0.24 and 0.27, respectively, for Baladi cows and 0.32, 0.26, 0.25 and 0.23, respectively, for cross cows.
4- Genetic correlation between all traits studied for the three genotype groups are moderate and positive, while, corresponding phenotypic correlations between different traits under investigation were small and positive.
5- The expected breeding values of cows (EBV’c) of the above traits for Friesian cows were 1270 kg, 29.03, 12.58 and 15.06 d, respectively, while, for Baladi cows were 583 kg, 25.5, 107 and 92.6 d, respectively, and for cross cows were 1144 kg, 200.5, 81.5 and 76.7 d, respectively.
6- The expected breeding values of sires (EBV’s) for Friesian cows were 801 kg, 14.7, 7.13 and 9.88 d, respectively, where, for Baladi cows were 314 kg, 109, 127.1 and 90.8 d, respectively, and for crossing cows were 423 kg, 110, 141.8 and 110.7 d, respectively.
7- The expected breeding values of dams (EBV’d) for Friesian cows were 911 kg, 22.85, 10.75 and 12.42 d, respectively, while, for Baladi cows were 258 kg, 90, 78.7 and 74.2 d, respectively, and for crossing cows were 316 kg, 23, 39.1 and 58.4 d, respectively.