Abstract: The Concentrations of five kinds of reproductive hormone in the peripheral blood of seven dairy cows are measured by radioimmunoassay throughout the oestrous cycle.FSH:mean value is 8.90±21 68ng/ml and 2.34±149ng/ml on the 1st day,the concentration is at the low level while the highest peak appears (peak values 28.58±64 45ng)on the eighth day.LH:The mean value is 4.13±10 68ng/ml,LH Lever 12hr 1ater after the period of heating onset is highest(peak values 29.15±16 62ng/ml),following the lower level.PRL:The mean value is 20.45士12.OOng/ml.There is a sharp variation during the whole period of heating onset·The three peaks appear on the first clay, the sixth clay,the fourteenth clay and the values are 43.1士28.62ng/ml,35.43士31.33ng/ml,34.88士27.58ng/ml,respectively. P4:The mean v clue is 2.96士1.85ng/ml.There is no sharp variation during the whole cycle.The concentration is 2.70士1.33ng/ml on the zero day.Following the platform shaped peak is formed from the eighth day to the twelfth day(peak value 3.O1一3.63ng/ml),the leve1 falls down until the period of heating onset begins, while one peak appears on the fifteenth day. E2:The concentration is at a lower level during the oestrous cycles.It arrives23.23士17.31ng/ml 12hr later after the period of heating onset,then falls down to the low level while the two peaks appear on the fifth clay and ninth clay.The elementary data of these five hormones and the relation of the variation among these five hormones are unraveled through this experiment.

Key words: Reproductive hormone, Radioimmunoassay(RIA), Dairycow

CLC Number: 

• S823.1