TLR5 interacts with bacterial flagellin, thereby playing a crucial role in defending the host against bacterial pathogens [57, 58], while CXCL8 plays a crucial role in recruiting and activating immune cells, particularly neutrophils, at sites of infection or tissue damage [59–61], suggesting that low-RFI beef cattle possess a more efficient immune response and host defense against infections. This evidence concerns the gene CXCL8 and infection.