The article presents reasons for farmers to increase concentration in dairy cow breeding. The most important concerns the decrease in the unit profitability of milk production caused by a faster growth rate of labor costs and prices of means of production purchased by farmers than the selling prices of agricultural products. The result of the trends was a decrease in the number of dairy farms and the number of cows. In 1996-2020, the number of dairy farms decreased by 85% (to 198 thousand), and the number of cows decreased by 28.7% (to 2,468 thousand units). As a result, the average size of a herd of cows increased from 2.64 in 1996 to 12.64 units in 2020. At the same time, the milk yield of cows increased by 85%. The territorial diversification of the cow population also deepened. In 2020, 69.2% of the cow population was located in the following voivodships: Mazowieckie (21.1%), Podlaskie (18.9), Wielkopolskie (13.0%), Warmińsko-Mazurskie (8.5%) and Łódzkie (7.7%). The analysis of the economic results of farms carried out in two periods 2008-2010 and 2018- 2020 showed that farms with at least 24 cows with a total milk production of 129 tons in the first period and 144 tons of milk in the second period turned out to be able to compete. Farms with 62 cows with a total production of 494 tons of milk were fully competitive in the second period.