The Usefulness of Antemortem Fecal Samples as an Alternative Diagnostic Specimen for the Etiological Diagnosis of Neonatal Calf Scours

Abstract

Practitioners commonly face a "diagnostic dilemma" when dealing with neonatal calf scours outbreaks. Most are aware that an ideal specimen for investigating an enteritis problem is an acutely ill, untreated, sacrificed, and immediately necropsied animal. Unfortunately in a diagnostic sense but understandably, the cattle producer does not see this as a very palatable approach. This reluctance is in part due to the fact that one calf represents a significant economic unit to the producer and because many times the animal can be saved with treatment. Therefore, many times the diagnostic lab does not receive acute cases to perform diagnostic tests upon and primary pathogens may be long gone due to chronicity. Postmortem autolysis is another important hindrance to diagnostic success. When calves are treated until they die, the window of opportunity to collect "fresh" tissue is no longer under the veterinarians control when compared to sacrificing the animal and immediately doing a necropsy and properly collecting specimens.

In contrast, swine producers are ready and willing to sacrifice live acutely ill piglets to determine a specific etiological diagnosis and subsequently enjoy a much higher diagnostic success rate (90% or greater). However, when traditional neonatal calf scour submissions (bodies and tissues) are utilized, the diagnostic success rate suffers greatly due to the submission of chronic and/or autolyzed specimens (success less than 70%). One solution to this "diagnostic dilemma" was to analyze and evaluate alternative diagnostic specimens. This South Dakota Animal Disease Research and Diagnostic Laboratory of SDSU conducted a 6 month study in 1993 with two purposes: 1. to determine the diagnostic success rate of antemortem fecal specimens from calves in the acute stages of diarrhea, relative to the diagnostic success of shipped tissue specimens and to whole bodies brought to the laboratory; and 2. to encourage the use of antemortem fecal specimens as an alternative diagnostic tool, if the study indicated usefulness.