Fig. 3. A histogram of WBC counts of Regressors (blue) and Progressors (red) at ultrasonographic grades 345, where the x-axis shows WBC levels and the y-axis shows the number of patients affected.
this study, treatment protocol on the study property typically involved antibiotic treatment of foals with grade 2 lesions and larger. Clinical R. equi pneu- monia had been all but eliminated on the property. Assuming the study year would have followed the patterns of the previous 12 years, 55 animals would have been treated with no clinical pneumonia cases if the established protocol had been continued. With participation in this study, only 19 animals were treated; 7 foals once they developed clinical disease and 12 once they met exclusion criteria. The disparity between treatment group numbers
exhibits the flaw of the established thoracic screen- ing program. Clients and veterinarians most likely initiate
R. equi prevention programs largely in response to significant clinical disease experienced historically. This may have been due to high morbidity rates and associated length of treatments, management changes, and intensity of labor involved with clinical cases in a previous year or it may have involved one or more significant (economic and/or emotional) mortality. It is assumed that continuation of a tho- racic screening program reflects client and veteri-
Fig. 4. A histogram representation of SAA levels of Regressors (blue) and Progressors (red) at ultrasonographic grades 45, where the x-axis shows SAA levels and the y-axis show the number of patients affected.
