Acute phase protein responses to uterine bacterial contamination in cattle after calving.

Repeated ultrasonographic examinations and collections of blood samples and uterine lumenal swabs between seven and 28 days after calving were used to examine the relative effects of bacterial contamination and involution of the uterus on the concentrations of acute phase proteins in the blood of 26 dairy cows. The severity of bacterial contamination, as determined by the total bacterial growth score, was a significant variable for the concentrations of the acute phase proteins alpha1-acid glycoprotein (P < 0.0001), haptoglobin (P < 0.05) and ceruloplasmin (P < 0.0001). In addition, the concentrations of alpha1-acid glycoprotein and ceruloplasmin were increased in the cows from which Escherichia coli (P < 0.0001) and Arcanobacterium pyogenes (P < 0.05), respectively, were isolated from the uterine lumen. Uterine involution, as determined by the decreasing diameter of the previously gravid uterine horn, was associated with a decrease in the concentrations of alpha1-acid glycoprotein (P < 0.005), haptoglobin (P < 0.05) and ceruloplasmin (P < 0.01). However, the response of the acute phase proteins to bacterial contamination was independent of the day on which the samples were collected, indicating that their concentrations were increased by bacterial contamination in addition to the changes associated with uterine involution.