Comparison of the haemogram between three-year-old Thoroughbred stayers and sprinters

Results of blood counts have been analysed in three-year-old racehorses in training comprising 77 colt stayers, 27 colt sprinters, 61 filly stayers and 35 filly sprinters. The distributions of haemoglobin, erythrocyte count and haematocrit were significantly higher in colt stayers compared to the other three groups. In fillies these values were also significantly higher in stayers compared to sprinters. The erythrocyte count was significantly higher in filly stayers compared to colt sprinters but there were no significant differences between haemoglobin or haematocrit values in these groups. No significant differences were found in the erythrogram between colt and filly sprinters. Absolute lymphocyte counts were significantly higher in the two filly groups compared with the colts. Eosinophil counts were significantly higher in the stayer groups compared to the sprinters. The ranges of values observed, within each of the four groups, for haemoglobin, erythrocyte count and haematocrit were narrower than previously recorded.