General anaesthesia (GA) and surgery could affect the kidney function in small animals. A decrease in systemic blood pressure coupled with loss of blood/ fluids during GA and surgery leads to decreased blood flow in the kidney and subsequent damage. It is not clear from the previous studies if the preventive administration of intravenous fluids in healthy animals undergoing routine surgery (e.g. ovariohysterectomy (OHE)) is beneficial. Data on perioperative acute kidney injury (AKI) are scarce in cats. Subclinical AKI may develop with routine surgeries that may be missed if the animal does not have overt clinical signs, and due to limited diagnostic methods available currently. Serum creatinine (SCr) and blood urea nitrogen (BUN) concentrations have traditionally been considered as “gold standard” to detect the renal impairment. But these markers may remain within reference range until 60-75% of the kidney is damaged. Novel urinary biomarkers that indicate AKI earlier than SCr and BUN have been extensively studied in humans in the perioperative period; No studies are available on the effect of GA and surgery on renal function in cats. Aims of this proposal are to compare the effect of GA and surgery (OHE), with or without IV fluid administration, on traditional and novel biomarkers of kidney injury. We expect that the changes in the novel biomarkers will reflect the kidney damage earlier than the conventional markers and will provide a valuable tool for early recognition of AKI and subsequent functional impairment.