The influence of genetic factors on milking characteristics in dairy cows

Object – to investigate the genetic factors influencing milking characteristics. Tasks – to collect and analyze the literature on the characteristics of milking cows; to collect the data and to form cow milk yield, fat, protein and milking databases in herd X; to assess the genetic factors on the characteristics of milking; to investigate the correlation between productivity and milkability characteristics; to create a gene bank of DNA samples of investigated cows that influence milking characteristics. The investigation was undertaken in AC \"Atžalynas\" in a group of 163 selected cows. The group of cows consisted of Danish Black and White, Danish Red, Holstein, Lithuanian Black and White, Old genotype of Lithuanian Black and White and Swedish Black and White. Milking data was collected from Windows ALPRO system which automatically records milking data during the milking process. Data was collected and created the folowing databases: milk yield per day (kg), fat yield per day (kg), the average milk yield of 7 days (kg), the maximum milk flow (kg/min.), milking speed (kg/min.), milking time (min.). Productivity data was taken from VĮ \"Žemės ūkio informacija ir kaimo verslo centras\". The productivity database consisted of the following data: day of milking, milk yield (kg), percentage of fat, fat (kg), percentage of protein, protein (kg). Blood samples were taken from the jugular vein using vacuum tubes from K2EDTA (Venoject, Belgium). The results show that in the study of the milking of cows the milk flow was on average 4,08 kg/min., milking speed was on average 2,36 kg/min., milking time was on average 6,36 min. The maximum milk flow was from the Danish Black and White breed of cattle at 4,60 kg/min., the largest milking speed was from Lithuanian Black and White at 2,63 kg/min., and the shortest milking duration of 5,42 minutes was from the Old genotype Black and White breed. The breed of cow statistically affected the production of milk (p<0,001). There was a 10,9 % yield (kg) variation, 23 % variation of the amount of milk produced per day, 19,7 % milk fat and 13 % indicators of a variation in milk protein. Milking characteristics were not significantly efected by the breed. The variation in milk quantity was the greatest difference between breeds of cow (p<0,001). There was a 13,1 % variation of the maximum milk flow rate, 22 % variation of the milking speed and 13,3 % milking time variation. There is a strong positive correlation between milk yield (kg) and the highest milk flow (kg/min.) (0,37; p<0,001), milk yield (kg) and milking speed (kg/min.) (0,5; p<0,001), milk yield (kg) and milking time (min.) (0,32; p