Phagocytic phenomena in the mammary gland of cows. IV. Ratio of milk and serum opsonophagocytic indices in healthy cows during the first lactation period

In the previous investigations (5, 6) it has been found that opsonophagocytic activity of serum was higher than that of milk. This phenomenon was quite independent on a test bacterial strain used in the studies. It was concluded, therefore, that this property, i.e. the ratio of serum opsonophagocytic activity to that of milk, was of unspecific character. This finding was made during chronic streptococcal mastitis, and it was confirmed by Canadian authors (2, 3). The described relation between the opsonophagocytic potency of serum and milk occurred also in acute experimental mastitis (4, 7). The purpose of this work, in which healthy cows were examined during their first lactation, was to confirm observations made in the previous investigations.