Associations between leptin, body condition score, and energy metabolites in Holstein primiparous and multiparous cows from 2 to 8 weeks postpartum

Abstract

The present study aimed to investigate the relationship between serum leptin and body condition score (BCS) during the postpartum period in Holstein cows. We also explored the potential associations with other metabolic traits and fertility parameters. Primiparous and multiparous cows were subjected to leptin analysis on calving day. Starting at the second week postpartum, cows underwent seven weeks of weekly monitoring of serum concentrations of NEFA, BHB, leptin, cholesterol, AST, and bilirubin. During study, BCS changes were recorded, and the genital tract was assessed by ultrasonography and some fertility parameters were evaluated. During the study period, primiparous cows showed a lower mean BCS (P < 0.05). Leptin concentrations between calving and 8 weeks postpartum were higher in multiparous cows than primiparous cows (P < 0.001). Between postpartum weeks 2 and 8, primiparous cows showed higher concentrations of NEFA, BHB, and AST and lower cholesterol concentrations. Multiparous cows showed greater largest follicle diameters and ovulated earlier. Primiparous cows showed higher intervals of calving-to-first insemination and calving-to-conception, more insemination indices for the conception. Improved cow metabolic and reproductive performance was associated with lower concentrations of NEFA, BHB, and AST; higher concentrations of leptin and cholesterol; and greater BCS change during the early postpartum period. Delayed ovarian activity in primiparous cows might be caused by lower postpartum concentrations of leptin and cholesterol.