Serum Calcium and Glucose as Predictors of Postpartum Reproductive Complications

Abstract

Objective: This research effort focused on determining cow-specific critical thresholds for serum calcium and glucose concentrations to predict the risk of postpartum reproductive disorders in Holstein dairy cows.

Methods: Eighty-two multiparous Holstein cows were enrolled in the study. Blood samples were collected at 14 days prepartum and at parturition to measure serum glucose and calcium levels. Diagnoses of retained placenta (RP), metritis, ovarian cysts, and dystocia were made by trained farm personnel within 40 days postpartum. Receiver operating characteristic (ROC) curve analysis was employed to establish predictive thresholds, and logistic regression models were used to assess associations.

Results: No significant difference was found in serum glucose concentrations between healthy and diseased cows at either time point. However, serum calcium levels were significantly lower at parturition in cows with metritis, RP, and in the overall unhealthy group. ROC analysis identified prepartum glucose (49.5 mg/dL) and prepartum calcium (8.4 mg/dL) as robust predictors for dystocia (AUC=0.917) and RP (AUC=0.946), respectively. Calcium levels at parturition were predictive of metritis (7.85 mg/dL) and general health status (7.9 mg/dL). Logistic regression revealed that cows with prepartum glucose below 49.5 mg/dL had an 8-fold increased odds of dystocia. Similarly, prepartum calcium below 8.4 mg/dL was associated with an 11-fold increase in the odds of RP. At parturition, calcium levels below 7.85 mg/dL and 7.9 mg/dL increased the odds of metritis and overall morbidity by 10 and 7 times, respectively.

Conclusion: This study demonstrates that prepartum glucose and calcium levels, along with calcium concentrations at calving, are significant risk factors for postpartum reproductive disorders. Monitoring these biomarkers could facilitate early intervention and improve herd health management.