Correlation between some micromineral serum levels and retained fetal membranes in transition holstein dairy cows.

The aim of this study was to evaluate the relationship between Se, Zn, Cu serum levels around calving and the incidence of Retained Fetal Membranes (RFM) in dairy cows. The study was performed during winter season on 40 pluriparus Holstein cows randomly chosen from the same herd. The animals, aging on average 49 months, were observed from 20 days before to 20 days after normal vaginal delivery. Blood samples were collected from jugular vein at 20, 10 and 2 days before calving, at calving day and at 2, 10 and 20 days after calving. The Authors considered RFM when placenta was not expelled within 24 h from delivery. RFM was observed in 14 animals (35%). Se, serum levels of cows with RFM were not significantly different from cows without RFM; Cu, serum levels were constantly lower in cows with RFM, but not statistically significant compared to cows without RFM (p > 0.05); Zn, serum levels were lower in cows showing RFM, reaching statistical significance on 2nd day after calving (640 } 190.90 vs 907.90 } 398.2 ng/ml; p < 0.05). Cows with RFM showed a tendency to low Zn and Cu serum levels while, as reported by other authors, no significant variation was found in Se serum levels. Based on the results of this study we can suggest that Cu and Zn could play a role in determining RFM; more investigations are probably necessary to clarify the effects of these microminerals on cows’ reproductive efficiency.