Özet:

This research was carried out at Bala State Farm to investigate for the milk yield traits, fertility traits and the effects of some environmental factors on these traits. The data were collected from 348 Holstein cows. Environmental factors were analyzed by Least Squares Method. The lactation milk yield, lactation length and dry period were determined 7704.25±111.90 kg, 325.62±3.65 days and 86.93±2.23 days, respectively. The effect of calving season on the lactation milk yield and dry period were found to be statistically significant (P<0.05, P<0.01, P<0.001). The age at first conception and age at first calving were calculated 528.53±5.58 days and 826.21±4.91 days. While the effect of year had significant on the age at first calving (P<0.05), the effects of season on age at first conception and age at first calving were determined to be insignificant. Least squares means were found to be 100.68±4.31 days for service period, 279.11±0.53 days for gestation length and 401.86±4.49 days for calving interval. While the effects of season, year and lactation number on the gestation length and calving interval were found to be insignificant, the effect of season on the service period had significant (P<0.05). In conclusion milk yield of Holstein cows reared in the Bala State Farm is satisfactory level for Turkey conditions. But there were determined some problems on the fertility.

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