Early warning for inactive ovaries based on liver function index, serum MDA, IL-6, FGF21 and ANGPTL8 in dairy cows

Postpartum inactive ovaries (IOs) in dairy cows reduce the economic returns of the dairy industry. It is related to energy metabolism disorder, inflammatory response and oxidative stress. The objective of this study was to investigate the association of liver function index (LFI) and serum cytokines at 21 days postpartum with IO and to predict the risk of IO in dairy cows. The blood of 60 parturient cows was collected through caudal root vein at 3, 21, 28 and 55 days postpartum. Ultrasonography was performed at 50 and 55 days postpartum to determine follicular development. With the median LFI as the standard, it was divided into high LFI (n = 30) and low LFI group (n = 30). A cohort study was used to analyse the risk of LFI to IO and t-test was used to compare the blood biochemical indicators of different LFI groups. Then, 12 cows (oestrus = 6 and IO = 6) were slaughtered 55 days postpartum. The differences of LFI, cytokines and biochemical indexes were compared, and data were analysed by t-test, Spearman’s correlation analysis, binary logistic regression analysis and receiver operating characteristic analysis. The results show that growth and development of follicles of low LFI dairy cows were impaired, the risk of IO increased by 2.67 times. Cows with lower LFI had energy metabolism disorders, increased inflammation and oxidative stress and decreased ability to resist oxidative stress at 21 days postpartum. LFI and serum MDA, IL-6, FGF21 and ANGPTL at 21 days postpartum can predict IO in dairy cows.Highlights The risk of inactive ovaries (IOs) in cows with low liver function index (LFI) will increase by 2.67 times, serum MDA, IL-6, FGF21 and ANGPTL8 at 21 days postpartum can predict IOs in dairy cows at 50–55 days postpartum. A high predictive risk of IOs in dairy cows occurred when the LFI was less than −3.18, MDA more than 3.62 mmol/L, IL-6 more than 23.68 ng/L, FGF21 less than 812.41 ng/L and ANGPTL8 less than 695.79 ng/L at 21 days postpartum