Characterization of white blood cell ratios in South American camelids presented at a veterinary teaching hospital

White blood cell (WBC) ratios are used as diagnostic markers for various inflammatory or tumor diseases as well as stress in a broad range of species. The aim of this work was to provide data on five WBC ratios (neutrophil-to-lymphocyte ratio [NLR], band neutrophil-to-lymphocyte ratio [BLR], band neutrophil-to-neutrophil-to-lymphocyte ratio [BNLR], band neutrophil-to-neutrophil ratio [BNR] and lymphocyte-to-monocyte ratio [LMR]) in South American camelids (SAC) and characterize their association with demographic and important diagnostic parameters. Medical records of 307 SAC (275 alpacas, 32 llamas) that were presented at a veterinary teaching hospital were evaluated retrospectively. WBC ratios were calculated based on hematologic results of the initial blood samples. The influence of species, sex, age, body condition score, WBC count, and anemia on those ratios was investigated using descriptive statistics and generalized linear models. NLR, BLR and LMR were found to be significantly influenced by age and WBC count. Associations of individual WBC ratios with species, nutritional status or an anemic condition could be detected. NLR was 4.32; 2.31-7.81 (median; IQR), BLR 0.24; 0.07-0.87, BNLR 3.66 × 10^-3; 1.17 × 10^-3 - 14.20 × 10^-3, BNR 0.06; 0.02-0.15 and LMR was 7; 3.54-14.67. Our data might serve as a basis for further studies on WBC ratios in SAC. The animals in this study showed a variety of underlying diseases. It should hence be noted that these values are orientation values and provide a representative overview of conditions in a clinic, but are not suitable as reference values for healthy animals.