KAYGISIZ, ALI/0000-0002-5302-2735WOS: 000271623400025The purpose of this study was to estimate the trends components of 305-days milk yield in Holstein Friesian Cattle Holstein cows raised at the Ceylanpinar state farm in Turkey between 1986 and 2007 years. The phenotypic, genetic and environmental trends for 305-days milk yield were found to be 106.91, 13.42 and 93.49 kg year(-1), respectively. Despite, there was a correct decision in selection environmental factors affected yield more. In this respect, continuing the improving environmental factors which is composed of maintenance, feeding, milking practices and barn is recommended
