Species specific husbandry and physiological functions of animals. Development quality and adaptation of group reared dairy calves at specific age periods and seasonal effects by birth periods and rearing conditions

Dairy calves (totally 83 animals) of a calving period from October till Apr il were used for long term measurements of heart rate and blood investigati ons at 5, 15, 40 and 60 days of age. Results from calves born within the tw o months October and November and those results from calves born during the period from December till April were tested for seasonal effects. Signific ant differences of mean values could be found for hemoglobin derivatives an d oxygen binding capacity of hemoglobin and for the plasma Ca and cortisol concentration at all age points. For some other variables significant diffe rences of mean values were observed at different age points. Correlations o f the variables between the sampling points were used assessing individual specificity and those of the changes of the variables during the course of the early rearing period to the starting values at 5 days of age were used characterizing individual adaptation processes at specific life ages. Mean changes of the physiological variables between the four investigation point s were different in the two groups. Establishing reference data and cutting points of physiological variables for clinical diagnostic tests and for as sessing suitability of calf rearing conditions for animal welfare and anima l protection aspects must be done carefully and most critical especially co ncerning the targets definitions and procedural aspects taking into conside ration age of calves, development quality and functional state of adaptatio n.