Use of systemic disease signs to assess disease severity in dairy cows with acute coliform mastitis

Objective-To evaluate the use of systemic disease signs for classifying sev erity of acute coliform mastitis in dairy cows. Design-Prospective cohort study. Animals-144 dairy cows. Procedure-Cows were examined at the time of initial identification of disea se (time 0) and classified as having mild, moderate, or severe disease on t he basis of rectal temperature, hydration status, rumen contraction rate, a nd attitude. A CBC and serum biochemical analyses were performed, and milk samples were submitted for bacterial culture at time 0 and 48 hours later. Results-69 cows were classified as having mild disease, 44 as having modera te disease, and 31 as having severe disease. Median WBC and neutrophil coun ts were significantly lower in cows with moderate or severe disease at time 0 than in cows with mild disease. Band neutrophil count was significantly higher at 48 hours and serum calcium concentration was significantly lower at time 0 and at 48 hours in cows with severe or moderate disease, compared with cows with mild disease. Twenty-eight, 51, and 77% of cows with mild, moderate, and severe disease, respectively, had > 100,000 colony-forming un its/ml of milk at time 0. The odds that a cow with severe disease would die or be culled were 3.6 times the odds for a cow with moderate disease and 1 1.2 times the odds for a cow with mild disease. Conclusions and Clinical Relevance-Results suggest that a classification sc heme based on readily observable systemic disease signs can be used to clas sify disease severity in cows with acute coliform mastitis.