[Relation between the biochemical composition of the blood of cows and variations in milk production].

A significantly lower alkaline phosphatase activity was recorded in the arterial blood of cows with higher milk efficiency. They also had higher sugar contents in their blood: highly significantly in arterial blood and significantly in venous blood after milking. As to the other blood components, the differences are low and insignificant. A significant positive relationship between the daily milk yield and the content of ash in blood (mainly in venous blood before milking), highly significant positive relationship between protein content in arterial blood and daily milk yield, and significant to highly significant negative relationship between the activity of alkaline phosphatase in arterial and venous blood before milking and the level of gamma-globulins in arterial blood were recorded in the group of cows with higher milk output. In the group of cows with lower milk production, significant to highly significant negative relationships were obtained between protein content in blood and the daily milk yield (in arterial and venous blood before milking).