Use of a clinical sepsis score for predicting bacteremia in neonatal dairy calves on a calf rearing farm.

Abstract

In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the internist. The objective of this study was to develop a predictive model for risk of bacteremia, based on a clinical evaluation system called the clinical sepsis score. Blood from 90 ill calves, 1- to 14-days-old from a calf-raising farm in the San Joaquin Valley of California was cultured. The calves were also scored according to a clinical score for hydration status, fecal appearance, general attitude, appearance of scleral vessels, and umbilical abnormality. Age, rectal temperature, heart rate, respiratory rate, and presence or absence of a focal site of infection were recorded. Prevalence of bacteremia was 31% (28/90). A logistic regression model indicated that high clinical score, presence of a focal infection, and increased age were associated with an increased risk of bacteremia in ill calves (P < 0.06). Calves for which the model predicted bacteremia with a probability > or = 40.8% were considered bacteremic, yielding acceptable sensitivity (75%) and specificity (71%) estimates. The predictive model was validated through a 2nd sampling of 100 calves (79 ill calves and 21 controls), of which 17 calves were bacteremic. The classification was 75% correct using the model, with an estimated sensitivity of 76% and specificity of 75%. Overall, results indicated that the model could be a useful tool for predicting bacteremia in ill calves in a clinical setting.