Aref, N-E. M., A. S. Sayed, A. M. Zahran, G. A. Abdelaal & E. A. Nasser, 2018. Flow cytometric analysis of somatic cells and oxidant/antioxidant profile in dairy cows with subclinical mastitis. Bulg. J. Vet. Med., 21, No 3, 347–357.

DOI: 10.15547/bjvm.1089

Flow cytometric analysis of somatic cells count (SCC) and oxidant/antioxidant status of cows with subclinical mastitis (SCM) were investigated in 75 lactating Holstein-Friesian cows (20 controls; 55 SCM cows). Milk from active quarters (n=280) and blood samples (n=75) were aseptically collected. Milk samples were subjected to California Mastitis Test (CMT), microbiologic examination and flow cytometric analysis. Blood and milk samples were analysed for malondialdehyde (MDA) concentrations and total antioxidant capacity (TAC). Microbiological examination revealed 3 major pathogens in a single or mixed infection: Streptococcus species (26.9%), Staphylococcus species (57.7%) and Escherichia coli (49.23%). Flow cytometric analysis showed significant increase (p<0.05) in inflammatory cells in milk of cows with SCM compared to control cows. Differential SCC was characte­rised by significant increase (p<0.05) in polymorphonuclear leukocyte (PMNL) counts compared to normal milk. Additionally, Staphylococcus infection alone or mixed with other lactopathogens resulted in dramatic increase in PMNL. There was a significant decrease (P<0.01) of TAC in plasma and milk (0.49 ± 0.04, 0.27 ± 0.03 mM/L, respectively) and significantly increased (P<0.01) serum and milk MDA concentrations (13.72 ± 0.3, 7.72 ± 0.17 nmol/mL, respectively) in SCM cows. In conclusion, differential SCC is a reliable index for early detection of SCM. Milk PMNL population can be used as a useful indicator for evaluation of udder infection. Additionally, a combination of MDA and TAC can provide complementary information about the health status of udder in dairy farms.

Key words: antioxidant, flow cytometery, mastitis, somatic cell