1Department of Genetics, Faculty of Veterinary Medicine, Uludag University, Bursa, Turkey
2Department of Animal Science, Faculty of Agriculture, Namik Kemal University, Tekirdag, Turkey
3Department of Biostatistics, Faculty of Medicine, Ordu University, Ordu, Turkey
4Department of Animal Science, Faculty of Agriculture, Ahi Evran University, Kirsehir, Turkey
5Department of Animal Science, Faculty of Agriculture, Ondokuz Mayis University, Samsun, Turkey
Department of Animal Science, Faculty of Agriculture, Ahi Evran University, Kirsehir, Turkey
*Corresponding author's e-mail: ertugrul.kul@ahievran.edu.tr
Online published on 4 November, 2017.
This study aims to determine the correlations between the test-day milk yield (TDMY) and the fat and protein content as well as the fat and protein yields in Holstein dairy cows and to investigate the effects of lactation period and sampling season on these parameters. The study material consists of 1.380 records of a total of 151 head of Holstein dairy cows raised on a private farm in Samsun province. In the study, the mean TDMY, fat content, protein content, fat yield and protein yield were recorded as 20.6±5.10 kg, 3.97±0.734%, 3.23±0.276%, 0.81±0.210 kg and 0.66±0.160 kg, respectively. The effects of lactation period and sampling season on the TDMY, fat content, protein content, fat yield and protein yield were found statistically significant (P<0.01). Statistically significant negative correlations were determined between the TDMY and the fat and protein content, but positive and statistically significant (P<0.01) correlations between the TDMY and the fat and protein yields. In conclusion, it might be stated that the effects of lactation period and sampling season should also be taken into account to improve milk yield and milk components.
Fat content, Holstein, Lactation period, Protein content, Test-day milk yield
