Abstract:

The purpose of this study is to investigate the environmental factors on the milking time milk yield of Red Holstein cows. For this aim, 172,826 morning milk yield (MMY) and 172,771 evening milk yield (EMY) data collected between 2001 and 2010 from a dairy farm in Aydin Province, Turkey were used. The THI is over 72 from June to August in the region. The effects of calving month, calving year, parity, lactation month and milking month on MMY and EMY were found to be statistically significant. For every month, year and parity, the MMY means were higher than those of the EMY. The peak daily milk yield was determined on the 46th day of lactation (31.7±0.013 kg). For parity, the highest milk yield means were detected for the third parity: 13.69±0.023 kg for MMY and 11.70±0.021 kg for EMY. In conclusion, taking precautions to protect the cows from heat stress especially for the cows calved in summer and keeping the milking interval equal for whole year would help increasing the milk yield.

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