Pilot study comparing hematologic and serum biochemical parameters in healthy horses (Equus caballus) and mules

Abstract

Values are known for horses and most donkey breeds but not mules. The current study was designed to establish reference ranges for hematological and biochemical parameters for clinically normal mules compared to horses. A mule is a cross between a mare and a jack (a male donkey, Equus asinus). A single sample was collected from nine mature mules and four-quarter horses owned by the U.S. Forest Service Pack String (Shawnee, CO). Rectal temperature (mule 37.3 C, horse 37.5), body condition (1 to 9), weight (mules 589.6 kg, horses 496.6), age (mules 10.3 yrs, horses 9.2), and sex (mules 5 geldings, 4 mares, horses 4 geldings, 1 mare) were recorded for each animal. All animals were on the same diet (grass and alfalfa mixed hay, no concentrate). A single 10 mL blood sample was collected from venipuncture of the jugular vein with an EDTA tube. Samples were analyzed for total erythrocyte, total red blood cell (RBC), white blood cell (WBC), hemoglobin (Hb), packed cell volume (PCV), platelet, mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV) and red cell distribution width (RDW). A statistical difference using the Mann-Whitney-Wilcoxon test was found when comparing weight, WBC, lymphocytes (Ly), monocytes (Mo) and mean corpuscular hemoglobin (MCV) (P < .05) (Table 1). Differences were not seen in temperature, NE, RBC, Hb, MCV, MCH, platelet count, MPV, fibrinogen, plasma protein, TSP, albumin, globulins, A/G ratio, calcium and creatine-phosphokinase. Parameters for mules compared to horse values were similar with the exception of WBC, Ly, Mo, and MCV, which were similar to values previously reported in donkeys [1]. Baseline hematologic and serum chemistry values for mules is invaluable information for those involved in management and disease investigation in the equid species. Future research will compare hematological and serum biochemical parameters in mature mules and hinnies with horses and donkeys.