Interleukins’ expression profile changes in granulosa cells of preovulatory follicles during the postpartum period in dairy cows

•Interleukin (IL) 4 expression was significantly altered during the postpartum period.•IL8 and IL15 were the most significantly induced during the postpartum period.•Correlation between increased BHB levels and induction of proinflammatory cytokines.•Interleukins analyzed were differentially regulated during follicular development.•ILs induced during the post-partum period were also induced 24 h post-hCG injection.