The mean IL-1α immunoreactive cell count in healthy cows on day 4 was statistically significantly greater than in subclinical mastitis- (p = 0.012) and in clinical mastitis-affected cows (p = 0.004), but not on day 5 (p = 0.312) and day 6 (p = 0.107). The gene discussed is IL1A; the disease is mastitis.