Abstract. Title of the paper: Hematological variables and plasma cortisol in dairy cattle kept loose house and in their newborn calves. Effects of some constant and variable factors
On 80 dairy cows (72 Holstein Friesian, 8 German Red and White, kept loose house) and on their newborn calves hemoglobin (Hb), hematocrite (Hk), mean corpuscular hemoglobin concentration (MCHC), plasma cortisol and body temperature (RT) and in calves saliva cortisol and body weight (KM) measurements were done and analysed considering lactation number (LANR) and gestation length (TD) of the cow, sex and KM of the calf, day time and type of birth (GV) and the time between parturition and measurement (ZGM). Type of birth was specified as GV1 (without assistance), GV2 (with moderate assistance by the herdsman, in some cases with mechanical support), and GV 3 (with heavy traction, most with mechanical support). The mean value of Hb and of MCHC was smaller and that of plasma cortisol was greater in calves comparing dams. In GV2 and GV3 the number of male calves was two times that of female calves. Mean Hb and Hk of cows were greater in GV2 comparing GV1 and GV3 but this difference was only significant for Hk between GV1 and GV2. In calves Hb, Hk and MCHC values became smaller from GV1 to GV3. Mean values of the differences calf-cow of Hb and Hk were significantly different between GV1, GV2 and GV3. Cows and calves with GV1 had significant smaller plasma cortisol concentrations than those with GV2 and GV3. Significant effects on calf plasma cortisol could be established for ZGM, GV, pCO2 and pH group and those on plasma cortisol of cows for ZGM and pCO₂ of calf blood. Saliva cortisol had a stronger correlation with plasma cortisol in calves of group GV1 (r = 0.749) than in those calves of group GV2 (r = 0.432). The Q-Q Plots of the day time of birth and plasma cortisol concentration confirmed effects of the type of birth suggesting a role for diurnal effects. Results show effects of birth assistance measures common used in dairy cattle production on the variation of physiological variables in cows and calves and they were discussed regarding development quality and the reactivity of calves as affected by delivery.