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This study was carried out to estimate the phenotypic and genetic parameters for the gestation length and birth weight of Brown Swiss cattle reared at the Bahri Bagdas International Agricultural Research Institute. The experimental material consisted of 891 calving records and 666 gestation length records between 1989 and 2000. The least- squares means of birth weight and gestation length were 35.6 kg and 284 days, respectively. Except for the effect of the dam's age on gestation length, all other factors investigated in this study had significant effects on both gestation length and birth weight (P < 0.05-0.001). The estimations of heritability and repeatability for birth weight were O. 10 and O. 15, respectively. Estimated repeatability for gestation length was 0.14. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate milk yield traits and some environmental factors affecting milk yield traits in Brown Swiss cattle reared at the Bahri Dagdas International Agricultural Research Institute. Between 1987 and 1998, 730 lactation records obtained from 273 cows were evaluated. The least-squares means of measured milk yield, 305-day milk yield, dry period and lactation duration were 3631 kg, 3332 kg, 97.1 days and 313.8 days, respectively. Both year and age statistically affected (P < 0.01-0.001) milk yield and lactation duration, but the calving season was not affected (P > 0.05). The effect of the year on dry period was also significant (P < 0.01), but the effect of age and calving season were not significant (P > 0.05). [ABSTRACT FROM AUTHOR]