0023-6152

AA00697606

25204

査読無

0023-6152

AA00697606

This study was conducted to investigate the environmental factors affecting milk yield traits of Turkish Brown cows raised at the Ulaş state farm under a sub–tropical climate. First the effect of calving years on actual milk yield, daily milk yield, 305–day milk yield, 305–day mature age milk yield, lactation duration and dry period days were investigated. In 2000 to 2006, the actual milk yield, daily milk yield, 305–day milk yield, 305–day mature age milk yield, lactation duration and dry period days were significantly related to calving years. Second the effect of calving times on actual milk yield, daily milk yield, 305–day milk yield, 305–day mature age milk yield, lactation duration and dry period days were detected. These data indicate that the peak milk yield is at the 5th–7th calving times with maturity in Brown Swiss cows reared in the Central Anatolia region in Turkey. We carried out the effect of calving season on the identical items. The seasons of calving affect actual milk yield, days of lactation duration and days of dry period. Cows that calve in winter have the highest actual milk yield. This could be due to stable nutrition during the important first lactation period to avoid cold stress. However, better management is required for cows calved in autumn that are under high temperature stress during an important lactation period.