Predictive markers in the late gestation period for retained placenta in black-pied dairy cows under field conditions in France.

A prospective ecopathogical survey was conducted in French commercial dairy herds located in Brittany. Previous production and reproduction data and blood parameters were used to identify predictive indicators of risk for retained placenta (RP) in Black-Pied cows. All the cows had delivered a single calf after a dry period of at least 30 d and had produced milk for at least 30 d. The cows with and without retained placenta were allocated to groups according to herd and interval between antepartum blood sampling and calving. Two groups of cows with (RP-positive group, n = 45) and without (RP-negative group, n = 184) retained placenta were compared. Univariate analysis indicated lower plasma glucose concentration, lower monocyte count and higher red blood cell count in the RP-positive group. A multiple logistic regression was run, with herd and blood sampling to calving interval as the fixed effects. It showed that a high red cell count and a low monocyte count were predictive indicators for retained placenta risk, which was found to be lower at third calving. Relationships of circulating indicators with placental retention etiology are discussed in terms of polyunsaturated fatty acid imbalance, its consequences on monocyte and erythrocyte functions, uterine motility and circulatory disturbances.