Effect of interleukin -6 level on reproductive performance in Holstein cows

Abstract: The current study was conducted in private dairy cows station located in middle of Iraq by using 80 samples of blood  during the period 2021 – 2022  in aim to determine the effect of IL-6 concentration on reproductive performance. Results showed  a significant effect (P≤0.01) of IL-6 level on reproductive traits parameters. Days open differed significantly according this interleukin and the highest days open was recorded in cows with low IL-6 level namely, 187.37 pg/ml. Service per conception differed significantly according to IL-6 level in blood plasma, the highest number of service per conception was recorded in cows with low IL-6 interleukin about 3.77 service. calving interval differed significantly according to IL-6 concentration, the longest period was noticed in cows with low IL-6 level compared with the shortest period which noticed in cows with moderate IL-6 level namely, 482.48 and 400.25 day respectively. Ovulation weakness differ significantly (P≤0.01) according to IL-6, the highest rate of infection was recorded in cows with high IL-6 level (63.64%) from total number about 33 cases while the lowest rate of ovulation weakness was noticed in cows with low IL-6 level namely, 21.21%.