Number of services per conseption and its relationship with dairy cow productive and reproductive traits

The aim of our study was to determine up to what extent the number of services per calving (NSPC) affects dairy cow productive and reproductive performance.The study contains data from the Latvian Agricultural Data center about 26888 Latvian Brown (LB) and Holstein Black and White (HBW) breed cows that were born from year 2005 -2010, closed at least 5 full lactations and were culled from herds.In data set we have included data about cow milk productivity (calculated in ECM), longevity traits and reproduction traits.The reproduction traits included the number of services per conception (NSPC), calving interval (CI) and calving to conception interval (CCI) in the first five lactations.The average lifespan of LB and HBW dairy cows was 3149.5 days and in this period 39570.6 kg ECM were obtained.LB breed cows were characterized by 23.5 days longer lifespan and by 6035.4 kg ECM lower lifetime milk productivity than HBW breed cows, but they showed higher reproduction trait scores than LB breed group.HBW cows had a significantly (p < 0.05) higher NSPC, CCI, number of milking days (MD) and CI than LB breed cows in all five analyzed lactations.The NSPC in the first lactation increased the calving age at the fifth lactationcows with NSPC in the first lactation > 4, fifth time calved 170.7 days in LB breed group and 190.8 days in HBW breed group later than cows with one NSPC in the first lactation.