Relationship between the prevalence of bovine viral diarrhea virus and animal welfare assessment, serum cortisol levels and hematological parameters in calves from three different Sicilian farms

Differences in management conditions between farms lead to different animal welfare levels between herds and contribute to the occurrence of some health disorders, including infectious disease. The aim of this study was to evaluate the relationship of prevalence of Bovine viral diarrhea virus (BVDV) and the changes in hematological parameters, serum cortisol concentration and welfare levels over the course of a year in calves of three farms from Sicily (Italy). For this purpose, 150 dairy Friesian calves in farm 1, 27 Limousine beef calves in farm 2 and 16 dairy Friesian calves in farm 3, aged 30 +/- 5 days, with body weight 40 +/- 6kg, were enrolled in the study. The welfare status of animals was assessed by the CReNBA. From each animal, blood samples were collected by coccygeal venipuncture at four time-point: in June (T1), in October (T2), in February ( T3) and in June of the next year (T4). The serum cortisol concentration and the hematological parameters, including white blood cells (WBCs), neutrophils (NEU), lymphocytes (LYM), monocytes (MONO), eosinophils (EOS), basophils (BASO), red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC) and platelets (PLT), were evaluated. No correlation between the prevalence of the infection and the CReNBA checklist was observed (P>0.05). A statistically significant change of the serum cortisol concentration and of hematologic parameters, except LYM and MCV, was observed in healthy calves from several three farms and in BVD infected calves from farm 2 and farm 3 throughout experimental period. According to the results gathered in the current study, it can be seen that the changes found in the investigated parameters were related to external and to internal factors in healthy calves and to direct or indirect action of the virus in BVD infected calves.