Schilddrüsenhormone bei Milchrindern in Laufstallhaltung nach der Kalbung und bei deren Kälbern. Effekte einiger konstanter und variabler Faktoren

Abstract. Title of the paper: Thyroid hormones in loose housed dairy cattle and in their newborn calves. Effects of some constant and variable factors
On dairy cows (72 German Holstein Friesian, 8 German Red Pied, kept loose house) and on their newborn calves thyroid hormone and body temperature measurements and in calves body weight measurements were done and analysed considering lactation number and gestation length of the dam, sex and body weight of the calf, type of birth, daytime of birth and measurement. For gestation length, body weight and lactation number no effects on thyroid hormones could be found. Birth course was specified as GV1 (without assistance), GV2 (with little assistance by the herdsman, in some cases with mechanical support), and GV3 (with heavy traction, most with mechanical support). In GV2 the number of male calves was twice that of female calves. Sex of calf influenced effects of birth type in case of T₄ and body temperature of the dam and effects of pH group in case of FT₃ of the calf. Calves born without any support had significant greater T₄, FT₄ and FT₃ concentrations than those with GV 2 and GV 3. Assisted birth types were significantly more frequent in pH groups pHG3 and pHG4 than in groups pHG1 and pHG2. In calves thyroid hormones had significant correlations with pCO₂ and pH of calf venous blood and with the time elapsing between birth and sampling. In dams of group GV3 the means of FT₄ and T₄ were smaller than those in dams of GV1 and GV2 but this differences were not significant.