Effects of racing on reticulocyte concentrations in Greyhounds

Abstract

Background Greyhounds have several hematologic variables that are outside of the respective reference intervals of other dog breeds. In addition, increases in HCT, total protein and HGB concentration, and RBC and WBC counts occur immediately after exercise; these values return to resting values within a few hour after racing. Objective This study evaluated the effects of exercise on the concentration of reticulocytes in circulating blood in racing Greyhounds. We hypothesized that reticulocyte numbers are significantly increased immediately after a race, and return to baseline within one to 2 h postrace. Methods Fifty actively racing Greyhounds at the Wheeling Island Racetrack and Casino were included in the study. Samples were collected by jugular venipuncture one day prior to racing at the kennel (resting), immediately after racing, and one to 2 h after the race (recovery). Reticulocyte counts were determined with an IDEXX ProCyte Dx Hematology Analyzer (IDEXX Laboratories, Inc., Westbrook, ME, USA). Due to a nonparametric distribution, the results were statistically compared using the Friedman test. Results Reticulocyte concentrations were significantly different among the 3 sample collection times (P < .0001). There was a significant increase in reticulocyte concentration immediately after racing (P < .001); one to 2 h after racing, the reticulocyte numbers decreased significantly (P < .001) to counts comparable to resting samples. Conclusion The increase in reticulocyte concentration is probably related to splenic contraction secondary to the release of catecholamines, although premature bone marrow release could also account for these changes. Thus, it is important to consider a Greyhound's activity and degree of excitement when interpreting selected hematologic data in a clinical setting.

Haematological and biochemical reference intervals in healthy racing and retired Italian Greyhounds

“…However, this may depend on the high analytical sensitivity of laser-based analysers rather than on a true reticulocytosis (Moritz et al, 2004;Tvedten and Moritz, 2010). This hypothesis is confirmed by a recent report on Greyhounds in which reticulocyte counts increased only after racing, possibly due to splenic contraction (Horvath et al, 2014).…”

“…Blood was collected at rest at least 7 days from a race in non-retired dogs, to avoid the effects of short exercise on blood parameters (Ilkiw et al, 1989;Horvath et al, 2014) from animals fasted at least for 12 h, and transferred to the laboratory at 4 8C within 18 h. Samples were collected within plans of health monitoring with the owners' informed consent. Therefore, according to the regulations of our Institution (Decision 2/2016 of the Institutional Ethical Committee) a formal approval of the Institutional Ethical Committee was not necessary.…”

Reticulocytosis in non‐anaemic cats and dogs

“…In concordance, reticulocyte counts were recently found to be increased in greyhounds after racing (Horvath et al . ). The authors hypothesised that splenic contraction due to catecholamine release might be responsible for the rise in post‐race reticulocyte numbers.…”

“…Their hypothesis is supported by their finding of increased numbers of circulating mature reticulocytes, which might be stored in the spleen, rather than immature reticulocytes, which are more likely derived from recent stimulation of erythropoiesis (Horvath et al . ). Whether exercise induces some level of premature release of reticulocytes from the bone marrow was previously researched using well‐trained human rowers.…”

Improved Cardiovascular Tolerance to Hemorrhage after Oral Resveratrol Pretreatment in Dogs

“…The circumstances of how our study animals were recruited had limited our ability to address the important issue of survival time after hemorrhage. It is important to note that race-trained greyhounds are highly adapted to anaerobic tissue metabolism during exercise, modulating their cardiovascular, hemostatic and homeostatic responses to hemorrhage [ 39 , 40 ]. Prolonged anesthesia (5 h in this study) might have interfered with the normal cardiovascular compensatory responses to bleeding.…”