Evaluation of milking properties of dairy cows in different populations during lactation

The scientific-investigative research was performed in the Animal breeding and nutrition department of the Veterinary academy of the Lithuanian Health Science University and in the 8 dairy farms in 2016 – 2019. 940 dairy cows were evaluated, of which: 379 Lithuanian Black and White populations and 561 Lithuanian red and red and white populations. During the research, a database was created based on data on the origin, milk yield and milkability traits of dairy cows. Cows were grouped by population, lactation stage and lactation month. Statistical analysis of the data was performed by analysis of variance (ANOVA). The aim of the thesis: To evaluate and compare milkability traits of dairy cows of different breeds in Lithuania during lactation. The goals of the thesis: To evaluate and compare the indicators of the high milk flow, milking speed, milking time and milk yield in Lithuanian dairy cows during different stages and months of lactation. The results of the research: Comparison of the average milkability traits of Lithuanian black and white and Lithuanian red and red and white cows during lactation revealed that the average milking speed (0.06 kg/min.) And the highest milk flow (0.13 kg/min.) In Lithuanian black and white populations. The milking time (10.62 s) was significantly shorter than that of Lithuanian cows (p0.05). The highest milking flow and the longest milking time in the morning and evening milking were up to 100 lactation days in both cows, while the highest milk flow was kept at the highest level till 200 lactation days (p>0.05). Evaluating and comparing average milkability traits of cows in different lactation months, it was found that the highest milking speed of both cows in lactation months II - III, milking time- II and high milk flow in lactation month IV (p<0.001). The highest milking speed and the longest milking time during morning and evening milking were in both lactating cows during the II lactation month and the highest milk flow in the 4th lactating month. In the morning all milkability trais were higher than in the evening milking (p<0.001). Comparison of the average milk yields of the studied cows showed that the milk tendency of the cows in both populations coincided with the tendency of the milking rate and was higher up to 100 days of lactation (p<0.001). The highest milking speed and the longest milking time during morning and evening milking were in both lactating cows during the II lactation month and the highest milk flow in the 4th lactating month. In the morning all milkability traits were higher than in the evening milking (p