Relationship between serum metabolites, body condition, peri- and postpartum health and resumption of postpartum cyclicity in dairy cows

Earlier postpartum cyclicity is associated with greater reproductive efficiency, which can result in increased dairy product yields. We determined the relationship between blood metabolites, body condition, and peri- and postpartum health and resumption of postpartum cyclicity in dairy cows. Blood samples were collected from 145 dairy cows at 4 and 2 weeks prepartum, after calving, and at 1, 2, 4, and 6 weeks postpartum to measure serum non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), glucose, total cholesterol, albumin, urea nitrogen, aspartate aminotransferase, γ-glutamyltransferase, calcium, magnesium, phosphorus, and progesterone. Body condition score (BCS) was assessed at the same time points. Uterine inflammation was evaluated 4 and 6 weeks postpartum by measuring uterine discharge using a metricheck instrument and uterine cytology using neutrophil levels. Cows were grouped based on progesterone concentration (resumption of ovarian cyclicity, ≥1 ng/mL) at 2, 4, and 6 weeks postpartum into a non-cycling (NCY) group (n=61) and a cycling (CY) group (n=84). NEFA concentration was higher in the NCY group than in the CY group throughout the study period (P<0.0001), whereas BHBA concentration was higher in the NCY group immediately after calving (P<0.05). Total cholesterol concentration was lower in the NCY group throughout the pre- and postpartum period (P<0.05 to 0.0001). Concentrations of albumin, urea nitrogen, and magnesium were lower during postpartum (P<0.05 to 0.0001). BCS was lower in the NCY group at 6 weeks postpartum (P<0.001). Metricheck score (P<0.05) and neutrophil levels (P<0.005) were higher in the NCY group at 4 weeks postpartum. The NCY group had a higher prevalence of dystocia (P<0.05) and metabolic disorders (P<0.005). In conclusion, our results indicate that minimizing the extent of a negative energy balance, as well as implementing prophylactic measures for dystocia, uterine inflammation, and metabolic problems are important factors for hastening the resumption of postpartum cyclicity, which is crucial to improve reproductive efficiency in dairy cows.