Combined and breed-specific RIs for hematologic, biochemical, and hormonal analytes in Chios and Florina adult rams

Clinical pathology investigations are essential to evaluate the health status and practice management of ruminants. Appropriate and accurate RIs are required for the interpretation of laboratory results. Despite substantial phenotypic differences and management-related disparities between male and female sheep, RIs in rams are sparse and limited by small reference populations and outdated methods.

The purpose of this study was to establish RIs for hematologic, biochemical, and hormonal analytes in adult rams using controlled preanalytic and analytic procedures, and to investigate whether breed-dependent partitioning of RIs is required.

Reference individuals were selected by a direct a priori method. Blood was collected from 128 healthy adult rams representing 2 Greek breeds (64 Chios and 64 Florina). Hematologic analysis was performed on the Advia 120, while differential WBC counts were manually performed on Giemsa-stained blood smears. Flexor E, AVL 9180 Electrolyte Analyzer, and Immulite 1000 were used for biochemical and hormonal analyses, respectively. Combined and breed-specific RIs were calculated using nonparametric and robust methods, respectively.

Five outliers were detected based on laboratory results. Partitioning of RIs, based on both statistical and nonstatistical criteria, was recommended for some of the analytes.

The RIs are in some agreement with those in the literature. The observed differences may be attributed to preanalytic and analytic factors. The RIs determined in this study can be used as a guide for the interpretation of laboratory results in rams and can potentially be adopted by veterinary laboratories, provided that similar equipment and reagents are used.