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Research article - Peer-reviewed, 2005

Haematological and bone marrow responses after administration of recombinant human erythropoietin (rhEPO) to horses

Lilliehöök Inger, Schuback-Nostell Katarina, Essen-Gustavsson Birgitta, Nyman Görel, Bondesson Ulf, Roberts Julia, Kallings Peter


Haematological and bone marrow responses were evaluated in three Standardbred trotters treated with 50 IU/kg bwt recombinant human erythropoietin rhEPO (Eprex®) intravenously three times a week for three weeks. Haemoglobin, haematocrit and red blood cell count increased at the end of the rhEPO-treatment and persisted increased for three to four weeks after treatment. The highest haematocrit levels, 24% above normal, was reached the week after the last treatment. Mean corpuscular volume (MCV) was slightly increased (about 3%) at the end of the treatment period and red blood cell distribution width (RDW) increased about 12 % during treatment and stayed high for about two weeks. No reticulocytes were found in peripheral blood. The bone marrow M:E ratio decreased to 0.3 on the day of the last rhEPO-treatment from pre-treatment M:E ratio of 0.6, which indicated erythroid hyperplasia. rhEPO was only detected in the sample collected 24 hours post final rhEPO dose. None of the samples were positive for rhEPO antibodies. In conclusion, treatment with rhEPO induced a polycythemia of about 25% that persisted for three weeks after treatment. Increased erythropoiesis was indicated by an increased RDW, a slightly increase in MCV and a reduced M:E ratio in bone marrow. Multiple doses of Eprex® did not give rise to the production of rhEPO antibodies in the horse


rhEPO; horses; haematology

Published in

Proceedings of the 15th International Conference of Racing Analysts and Veterians, Dubai
2005, pages: 509-514
Publisher: R & W Communications (Newmarket), Suffolk, UK