Reference intervals for total protein concentration, serum protein fractions, and albumin/globulin ratios in clinically healthy dairy cows

The aim of the current study was to evaluate total serum protein concentration measured by the biuret reaction as well as albumin and globulin protein fractions determined by agarose gel electrophoresis. These data were used to establish reference intervals in dairy cows of different ages. Blood was collected from 111 clinically healthy Modicana dairy cows by means of jugular venipuncture. Reference intervals (mean standard deviation) were determined for total protein (67.54 +/- 11.53 g/l), albumin (31.86 +/- 4.60 g/l), alpha(1)-globulin (5.77 +/- 2.20 g/l), alpha(2)-globulin (5.84 1.90 g/l), beta-globulin (7.46 +/- 1.94 g/l), and gamma-globulin (16.73 +/- 4.54 g/l) concentrations as well as for albumin/globulin (A/G) ratio (0.88 +/- 0.43). Values from 2-, 3-, 4-, 5-, and 6-year-old cows were compared statistically. One-way analysis of variance showed age-related differences for alpha-globulin and beta-globulin fractions only. The results of the current study provide reference intervals for total protein concentration as well as albumin and globulin protein fractions in 2- to 6-year-old dairy cows.