Effects of tetracycline on hematological pattern of calves.

Introduction: Tetracycline may cause adverse reactions in animals and humans, interacting with the hematopoietic system (1,2,3). The aim of the Authors was to evaluate the effects of oxytetracycline on bovine hematic cells. Materials and methods: Eight half-breed “Piemontese” calves, eleven m.o., clinically healthy, were treated with oxytetracycline hydrochloride and divided into two groups of four: Group I received a single dose of 10 mg/Kg b.w., IM; Group II was treated at the same dose for 3 consecutive days. Blood samples were taken from each animal before (basal sample) and 1,3,5,15 days after the administration to determine the following haematological parameters: complete blood count (CBC), eosinophil count, morphological examination of the blood smears and Arneth count. The data were expressed as means ± SD and were elaborated using Student’s t-paired test (software program ANOVA CLR). Results: The data obtained showed a significant increase (P<0.02) in relative number of neutrophils in Group II only 1 (38.75±6.29%) and 3 (44±0%) days after administration. Significant changes in the other haematological parameters were not observed, neither within each group nor comparing the two groups. Conclusions: The present study, in the context of a research project on adverse reactions caused by drugs, allows us to point out that, in calves, tetracycline administration caused significant increase of neutrophils. Ours studies are still in progress to evaluate the possible functional alterations in neutrophils