AppIication of Differential Inflammatory Cell Count as a Tool to Monitor Udder Health

摘要

A flow cytometric technique called differential in- flammatory cell count was standardized by staining bovine peripheral blood leukocytes with a combination of DNA binding dyes SYBR green 1 and propidium iodide in water. Leukocytes were also stained with pro- pidium iodide in detergent to determine total cell count. Differential inflammatory cell count assay was evalu- ated with individual quarter milk samples from 13 cows. Cows were sampled at weekly intervals for 3 wk and assayed for total cell count, mononuclear leukocyte count, and polymorphonuclear leukocyte count. Simul- taneously, milk samples were evaluated by the conven- tional electronic somatic cell count (SCC) technique. Somatic cell count positively correlated with total cell count (r = 0.9), mononuclear leukocyte count (r = 0.8), and polymorphonuclear leukocyte count (r = 0.89). Quarters with SCC > log_10 5.4 had a higher total cell count, mononuclear leukocyte count, and polymorpho- nuclear leukocyte count and were more often culture positive compared with quarters with SCC < log_10 5.4 Quarters that were culture positive on all three test occasions had a higher proportion of polymorphonu- clear leukocytes (33 to 49/100) compared with quarters that were culture negative on all three test occasions (17 to 25/100). The findings of this study suggest that differential inflammatory cell count assay has the po- tential to evolve as a new technique for evaluation of udder health status.