Physiological and pathological factors influencing bovine serum albumin content of milk.

Concentrations of albumin from bovine blood serum were measured by radial immunodiffusion of 480 milk samples. Content in milk was not affected by content in serum, lactation number, or location of quarters. Bovine serum albumin concentrations in milk increased at the end of lactation (270 days) compared to the beginning (30 days) and at midlactation (150 days). Uninfected quarters had a mean concentration of serum albumin of .193 mg/ml. This was less than means for quarters infected by minor pathogens (.242 mg/ml) and by major pathogens (.284 mg/ml). Distributions of concentrations related to infection status, however, overlapped substantially. Somatic cell count was correlated .53 with concentrations of blood serum albumin in milk. About 32% of quarters infected by major pathogens had fewer than 500 x 10(3) cells/ml, whereas 47.5% of them had serum albumin content less than .2 mg/ml. For subclinical infections, concentration of serum albumin markedly increased when somatic cells were more than 1,000 x 10(3) cells/ml.