Prostaglandin F2 alpha and prostacyclin imbalance in cows with placental retention: new findings.

The aim of this work was to investigate possible differences in peripheral blood concentrations of 13, 14 dihydro 15 keto PGF alpha (PGFM) and 6 keto PGF1 alpha (PGIM), between dairy cows retaining (RP) and not retaining (NRP) their placenta. Blood samples were collected 5, 30, and 60 minutes postpartum from 8 RP and 17 NRP cows. PGFM concentrations were significantly lower in RP cows than in NRP cows 60 minutes after birth (8156 pg/ml vs 12016 pg/ml; P less than or equal to 0.05). There was a significant rise of PGFM levels between 30 and 60 minutes in NRP cows (6225 pg/ml vs 12016 pg/ml; P less than or equal to 0.01), while in RP cows PGFM levels remained fairly constant along the period studied. No significant differences were found between RP and NRP cows regarding PGIM levels during this period although absolute values were slightly higher in RP cows. The PGFM/PGIM ratio was significantly higher 60 minutes postpartum in NRP cows than in RP cows (15.5 vs 8.8; P less than or equal to 0.01). This ratio increased significantly in NRP cows between 30 and 60 minutes (7.2 vs 15.5; P less than or equal to 0.01), a pattern not observed in RP cows. There was no correlation between PGIM and PGFM levels during the first 60 minutes postpartum in the NRP cows. However, the same correlation was significantly positive in the RP cows (r = 0.75; P less than or equal to 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)