Risk assessment and consequences of retained placenta for uterine health, reproduction and milk yield in dairy cows.

The objective of the study was to determine the value of metabolic indicators characterising the energy and acid-base metabolism of dairy cows for predicting the risk of retained placenta (RP). The connection between RP and different factors analysed, and the effect of RP on the development of puerperal metritis (PM) as well as on reproduction and milk production was studied. A total of 105 Holstein-Friesian cows were included and sampled between days -14–0 prepartum and then on days 4, 10–14, 28–35, 56–63 and 84–91 postpartum, for metabolic tests. From day 4, at times coinciding with the days of metabolic sampling, uterine involution and metritis were monitored by clinical examination, and from days 28–35 ovarian activity was monitored by ultrasonography. On days -14–0, the plasma non-esterified fatty acids (NEFA) concentration showed a positive Odds Ratio (OR) 102.1, P < 0.05; while urinary net acid-base excretion (NABE) exhibited a negative correlation (OR 0.99; P < 0.05) with the odds of RP. NEFA and NABE were negatively correlated (Pearson’s coefficient: -0.24; P < 0.05). Ketonuria of grade ≥ 2+ increased the probability of RP (OR: Infinite; P < 0.05). On day -14–0 prepartum, elevated plasma NEFA concentration, decreasing urinary NABE and grade ≥ 2+ ketonuria indicates a higher risk of RP. The odds of RP were not influenced by parity, sex and viability of the calf, and the calving assistance. RP increased the risk of PM (OR: 27.3; P < 0.0001). The RP alone did not exert an influence on the metabolic status, reproductive performance or milk production of cows.