Pro-inflammatory cytokines as indicators of health status around calving in dairy cows.

The transition period in dairy cows is characterized by temporary decline in immune efficiency, increasing susceptibility to metabolic and infectious diseases. Pro-inflammatory cytokines (PIC) play central role in coordinating immune responses and initiating the acute phase reaction (APP). This study aimed to determine whether calving itself influences PIC release and to explore the association between cytokine dynamics, metabolic changes, and development of clinical disorders. Blood samples were collected from 12 Holstein Friesian cows from -7 to 7 days relative to calving and analysed for plasma concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Dry matter intake and health status were recorded daily, and cows were categorized as healthy (n = 7) or diseased (n = 5; showing ketosis, milk fever, mastitis, and diarrhoea within the first week postpartum). A comprehensive metabolic profile was also assessed. When considering all cows, calving had no significant impact on PIC release. However, diseased cows displayed elevated TNF-α concentrations (P < 0.05) from -7 to 0.5 days prepartum, a trend for higher IL-6 concentrations from -1 day, reaching significance (P < 0.05) at +1 day, and increased IL-1β concentrations from -2 to +3 days. Compared with healthy, Diseased cows also showed reduced DMI and a stronger APP, reflected by significantly (P < 0.05) increased haptoglobin and ceruloplasmin, reduced albumin, and elevated zinc concentrations. In this exploratory cohort, cows that developed postpartum disorders showed higher prepartum cytokine concentrations. These findings support the hypothesis that increased prepartum inflammatory tone is associated with poorer transition adaptation, but larger prospective studies are required before predictive claims.