from the onset of oestrus until day 4 of gestation , serum concentrations of lh and progesterone were negatively correlated ( r = 0.67 , p less than 0.01 ) , but from days 5 to 28 a positive correlation ( r = 0.80 , p less than 0.01 ) was noted .
C0032961
gestation
C0033308
progesterone