When evaluating a veterinary video endoscope, prioritize the insertion tube diameter (e.g., 3.0mm to 8.5mm) to ensure it fits the specific animal size (small pets vs. large animals). Look for high-definition CMOS sensors with at least 1,000,000 pixels to ensure clear visualization of mucosal structures. Additionally, check the working channel diameter; a channel of 2.0mm to 2.8mm is essential for passing biopsy forceps or suction tools. Ensure the device offers 4-way angulation (Up/Down/Left/Right) for comprehensive maneuverability within the gastric or respiratory tracts.