Abstract
Background:
Cat urolithiasis is more common in male orchiectomized cats.

Aim:
This study aimed to determine the effect of orchiectomy on productive performance, physiologic, hematologic, and blood chemistry parameters, renal function, and electrolyte handling in healthy adult cats.

Methods:
Ten male, 2-3 years old, 4.7-5.9 kilograms, with a moderate body condition score (BCS), and clinically healthy domestic cats were used in this study. The animals were divided into two groups: the ORCH group and the SOC group. Before surgery, daily weight gain, food intake, water intake, and urine volume were recorded, and urine pH and urine ammonia excretion were measured. Furthermore, vital signs, urine specific gravity, and UPCR were measured, and clearance studies were conducted. The biological, clinical, and renal function parameters were measured 5 weeks after surgery, as they were before surgery.

Results:
Orchiectomy in adult male cats increased productive performance (weight gain and food intake) without altering physiologic, hematologic, and metabolic parameters. The serum testosterone concentration in orchiectomized animals was significantly lower than that in the SOC group (P<0.05). The GFR of the ORCH group decreased significantly after orchiectomy, whereas that of the SOC group remained unchanged. The renal handling of electrolyte values of ORCH 5 weeks post-orchiectomy did not differ from those before the surgery or in the SOC group. All parameter values were within the physiological reference range for healthy cats.

Conclusion:
Orchiectomy had a short-term effect on productive performance but no negative impact on physiologic, hematologic, metabolic, or renal handling of electrolyte parameters in healthy adult male cats with sexually intact cats. However, there is a decrease in GFR, urine pH, and urine specific gravity and an increase in urine ammonia excretion. Therefore, further research is needed to determine the long-term impact of orchiectomy in cats.

Key words: Orchiectomy, Cat, Renal function, Electrolytes.