Effect of Calving Season, Calving Year and Lactation Number on the Milk Yield Traits in Holstein Cows Raising in Şanlıurfa

The aim of the present study is to investigate the impact of some environmental factors on the descriptive values of milk yield characteristics in Holstein cows. For this purpose, a total of 241 lactations belonging to 62 Holstein cows had been kept as breeders in a private establishment were evaluated for 7 years in terms of milk yield. When the recording system of the establishment was examined, the average values of lactation yield (LY), corrected 305 day milk yield (305-dMY), average daily milk yield (ADMY) and lactation length (LL) were 9356.2±126.1 kg, 8549.2±105.8 kg, 28.0±0.3 kg and 315.0±2.3 days, respectively. The least mean squares (LMS) of LY was calculated as 9324.9 kg. It was found that the effect of the calving season on the LY was statistically significant (P