DAIRY CHEMISTRY AND BIOCHEMISTRY seasonal trend: the ph of colostrum is about 6 but increases to the normal value of about 6 6-6. 7 shortly after parturition and changes little until late lactation, when the ph raises to as high as 7. 2, i.e. approaches that of blood (pH 7. 4)due to degeneration of the mammary cell membrane. The pH of milk also increases during mastitic infection(e.g 6.8-6.9), due to the influx of constituents from blood Figure 5.5 Correlations between the concentration of sodium and potassium(a) and sodium and chloride(b)in bovine milk.246 DAIRY CHEMISTRY AND BIOCHEMISTRY seasonal trend; the pH of colostrum is about 6 but increases to the normal value of about 6.6-6.7 shortly after parturition and changes little until late lactation, when the pH raises to as high as 7.2, i.e. approaches that of blood (pH 7.4) due to degeneration of the mammary cell membrane. The pH of milk also increases during mastitic infection (e.g. 6.8-6.9), due to the influx of constituents from blood. X Figure 5.5 Correlations between the concentration of sodium and potassium (a) and sodium and chloride (b) in bovine milk