Blood Gases, Acid-Base Status And Plasma Lactate Concentrations In Calves With Respiratory Diseases

The purpose of this study was to evaluate in calves the effects of respiratory diseases of various severities on blood gases, acid-base balance and plasma lactate concentration. We included in the study 128 calves with clinical signs of various severities and outcomes of respiratory disorders. The age of the calves ranged from 1 to 12 months. According to the clinical findings, course of the disease and time of blood collection, the sick calves were divided into three groups: RD 1 (n=34) – calves with moderate clinical signs; RD 2 (n=73) – calves with severe respiratory symptoms and RD 3 (n=21) – calves with severe respiratory symptoms and died within 48 hours after blood sampling. Into the study we also included one group of 28 clinically healthy calves. In the arterial blood we evaluated: blood pH, partial pressure of carbon dioxide – pCO₂, partial pressure of oxygen – pO₂, concentration of actual bicarbonate – HCO₃⁻, base excess – BE, and saturation of hemoglobin by oxygen – O₂-sat. The concentration of lactate was determined in the blood plasma. Significant effects of health status and severity of respiratory diseases were recorded in all the evaluated variables. Marked hypoxemia and hypercapnia were found in calves with severe respiratory disorders and in animals that died within 48 hours after blood collection. In most calves, the acid-base changes were characterized as compensated respiratory acidosis. The highest mean lactate values were recorded in calves that died within 48 hours after blood sampling. The presented results suggest the usefulness of the analysis of blood gases and acid-base status in the evaluation and prognosis of various degrees and severity of respiratory diseases in calves, and in monitoring the patient response to treatment. Although plasma lactate analysis is less consistent with the severity of respiratory diseases, it might be helpful in the indication of an untreatable stage of the disease and upcoming death.