What is the daily maintenance fluid rate for adult cats?

• A. 50 ml/kg/day
• B. 45 ml/kg/day
• C. 40 ml/kg/day
• D. 60 ml/kg/day

Answer: (B)

Maintenance fluids provide the daily amount needed to replace normal losses in a healthy adult cat. For cats, a typical maintenance range is about 40–60 ml/kg/day, so 45 ml/kg/day sits right in the middle and is commonly used as a default starting rate when no other factors demand more or less fluid.

To put it into numbers you can use in practice: multiply the cat’s weight in kilograms by 45 to get the daily fluid volume in milliliters. If delivering through an IV, that rate equals about 1.9 ml/kg/hour (roughly 2 ml/kg/hour). For a 4 kg cat, that’s about 180 ml per day or ~7.5 ml/hour. Remember, adjust up or down if there are factors like fever, vomiting, diarrhea, dehydration, or kidney disease that change fluid needs.