iarjetIARJETIARJET2708-5163https://doi.org/10.47310/iarjet.2021.v02i01.003Association between Age at First Calving and Milk Yield in Holstein Cows reared in PelagoniaVesnaKarapetkovska -HristovaZarkoBebicBorcheMakarijoskiBardhylLimaniGodswillNtsombohNtsefongFaculty of Biotechnical Sciences , University of St. Kliment Ohridski, Bitola, R.N.MacedoniaUniversity of Tetovo, Faculty for Agriculture and Biotechnology, Tetovo, R.N. MacedoniaDepartment of Plant Biology, Institute of Agricultural Research for Development, Department of Valorisation and Innovation, Yaounde-CameroonThe objective of this study was to analyse the influence of the age at first calving on the length of lactation and the milk yield of Holstein – Friesian cows. In this survey, sixty primiparous cows were analysed, divided in three groups (A-early, B-middle and C-late). All the research parameters were taken from the farm’s book keeping records. LSD method was used to calculate the statistical significance of the differences in the seasons and the groups of cows to a significance level of 0.05 and 0.01. There was a significant difference of the parameter daily milk yield between the groups A and C, p<0.05. Group B showed significant difference p<0.05 compared to group C. The results obtained for the 305 day lactation suggested that group A was significantly different (p<0.05) compared to group B. There was no significant difference in the length of lactation among the groups of the cows. With this study we have determined the optimal age for calving of the Holstein breed in the Pelagonia region farms to achieve better milk production.