Haematology of the racehorse. A recent study of thoroughbreds in Victoria.

The research analyzes blood samples from Thoroughbred racehorses in Victoria, finding differences in results based on different variables such as the horse’s demeanor and storage conditions of the samples. Possible normal ranges for several blood values are established.

Research Method

• The study involved the analysis of 216 blood samples from 136 Thoroughbreds in 17 different stables. Blood samples collected were subjected to different laboratory tests and analysis.
• The horses’ behavior at the time of blood collection was observed and noted. The conditions were classified as placid, timid, apprehensive, or excited.
• The samples from eight stables were stored overnight at 4°C before being analyzed. The influence of this storage condition on test results was investigated.

Findings

• Lower averages and lesser variability in test results were found in this study compared to previous ones. These differences were partly attributed to the measures taken to keep the horses calm during blood collection.
• The study found that horses’ demeanor affects certain blood values. Excited horses had higher red and white blood cell counts, eosinophil count, hematocrit (PCV), hemoglobin (Hb), and total protein levels. On the other hand, timid and apprehensive horses did not show these variations.
• Blood samples stored overnight showed differences in some parameters. Higher mean corpuscular volume (MCV), PCV, mean corpuscular hemoglobin (MCH), and protein levels and lower mean corpuscular hemoglobin concentration (MCHC) were observed. The variations were hypothesized to be due to possible changes in red blood cells during transport and storage.
• The serum total protein levels were within the range reported in previous studies involving different horse breeds. However, albumin level and the albumin/globulin (A/G) ratio were higher than those reported in previous studies.
• Following the removal of 14 samples with abnormalities in white blood cell count, normal ranges were established for red and white blood cell counts, hemoglobin, hematocrit, MCV, and MCH. However, because of high variability, skewness, and kurtosis, the use of erythrocyte sedimentation rate (ESR) and total eosinophil count (TEC) were doubted.

Conclusions

• The study highlighted the effects of the horses’ demeanor at the time of blood collection and the storage conditions of samples on the results of blood tests.
• It reaffirmed the importance of calming horses before blood collection and careful handling of samples.
• The research also contributed to the understanding of normal ranges of key blood parameters in Thoroughbred racehorses.