Short communication. Effects of some environmental factors and extended calving interval on milk yield of Red Holstein cows

摘要

The effects of extended calving interval (CI), calving month, calving year and parity on lactation length (LL), lactation milk yield (LMY), the first 305 days milk production of the lactation (305-dMY) and daily milk yield (DMY) of Red-Holstein cows were investigated. A total of 286 CI and lactation records were collected from 116 cows in a dairy farm located in Aegean Region of Turkey between 2001 and 2010. The CI data were divided into three classes: CI12 (12 months), CI15 (15 months) and CI18 (18 months). The CI class affected LL (p0.05) and by 15.9% in CI18 (p<0.01). Because of the higher temperature and relative humidity in summer months, it is advised that some extra precautions need to be taken to compensate the adverse effects of heat stress in cows in the region. In addition, extending CI from 12 to 15 months did not cause any significant production losses; however extending CI to 18 months resulted in a significant decrease in DMY.