The influence of subclinical mastitis on the protein composition and protease activities of raw milk from lactating Thai-crossbred dairy cows

Background and Aim: Mastitis in dairy cattle is associated with a high rate of morbidity death, which has major implications for milk production quality. This study aimed to investigate the protein component activity matrix metalloproteinase-2 (MMP-2) -9 (MMP-9) raw samples different testing scores determined using California mastitis test (CMT). Materials Methods: Thirty cows were employed study, from each quarter was tested subclinical (SCM). According results CMT, classified into five categories: Healthy (score 0), trace T), weakly positive 1), distinctly 2), strongly 3) somatic cell count (SCC). The total analyzed Bio-Rad assay, composition sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. In addition, gelatin zymography used evaluate changes proteolytic abilities. Results: Milk CMT 1 3 had highest levels (32.25 ± 12.60 g/L 32.50 7.67 g/L, respectively), while healthy (CMT score 0) only 6.75 1.64 g/L. Globulin lactoferrin significantly increased compared those other scores. bovine serum albumin level 2 (p < 0.05) higher than No significant differences casein abundance found among Results analysis activities demonstrated that MMP-9 Conclusion: content gelatinolytic drastically altered by number SCC, mainly due SCM. Keywords: protein, protease activity, mastitis, Thai-crossbred cows.