[Heart rate frequency and constitutional features of high yielding dairy cows in intensively managed and environmentally protected pasture].

The heart rate measured continuously in grazing cows over 24 hours is significantly different during specific behavioural patterns of an animal and is influenced by the stage of pregnancy of the cow. Repeated measurements of blood urea, creatinine, total protein, albumin and glucose concentration in these animals permit conclusions about the changes of body weight and of the liver function and hormonal integration of energy substrate supply. Living on pasture during the summer period the cows showed the lowest hemoglobin content and hematocrit level of the blood, which increased when the animals were housed in autumn or when near the end of their final trimester of pregnancy. Important differences, especially in the blood values, were found between the groups and within the groups between younger and older cows.