Cortisol measurements, biochemical and hematological parameters as biomarkers of Cunero cattle welfare during pre-slaughter handling in the Apurimac Region of Peru

Introduction For Cunero cattle, hematological parameters and biochemical biomarkers may serve as potential indicators of pre-slaughter stress, though their functional utility requires further validation. These measurements are essential for evaluating animal welfare when they fall within physiological ranges. Methods Blood samples were collected from the coccygeal vein of 100 Cunero cattle (50 females and 50 males) after they were transported from the Apurimac highlands to the municipal slaughterhouse in Abancay. Serum cortisol levels were quantified using a competitive ELISA test. Glucose, lactate, urea, creatine kinase (CK), and lactate dehydrogenase (LDH) concentrations were determined by spectrophotometry. Hematological parameters (red blood cells, hematocrit, hemoglobin, and white blood cells) were also analyzed. The Benjamini-Hochberg procedure was used to calculate adjusted p-values and control the false discovery rate resulting from multiple testing across ten physiological variables. Effect sizes and their 95% confidence intervals were calculated for the sex comparison using rank biserial correlation for U Mann-Whitney test and Cohen’s d for student’s t-test. Results and discussion The median cortisol level in the Creole × Holstein reference group was 4.50 μg/dL. No statistically significant difference was detected in cortisol levels between female and male Cunero cattle, with median (IQR) values of 21.65 (8.50) and 23.00 (10.10) μg/dL, respectively. No statistically significant differences in glucose, lactate, urea, and lactate dehydrogenase concentrations were detected by sex (p > 0.05). However, creatine kinase levels were higher (p< 0.001) in males than in females, with median (IQR) values of 278.72 (36.51) IU/L and 227.64 (52.04) IU/L, respectively. Likewise, higher values of hematocrit, hemoglobin, red blood cell count, and white blood cell count were observed in males than in females. Conclusion The serum cortisol levels and biochemical profiles of Cunero cattle observed in this study suggest the need for further research to confirm potential pre-slaughter stress indicators. Sex-associated differences were observed in key hematological parameters.