To determine the circulating blood volume of dogs, we need to consult standard veterinary references on the subject. Let's evaluate the options provided:
A) 40 to 60 mL/kg
B) 60% of their body weight (BW)
C) 80 to 90 mL/kg
D) 40% of their body weight (BW)
### Step-by-Step Solution:
1. Understand the units and percentage representations:
- mL/kg refers to milliliters of blood per kilogram of body weight.
- Percentages (e.g., 60% and 40% of body weight) represent proportions of the dog's total body weight.
2. Evaluate each option:
- Option A: 40 to 60 mL/kg
Standard veterinary references indicate that dogs typically have a circulating blood volume within this range. This means that for every kilogram of body weight, a dog has approximately 40 to 60 milliliters of blood.
- Option B: 60% of their BW
This would suggest that more than half of a dog's body weight is composed of blood, which is highly unlikely. The blood volume is usually much less proportionate to the total body weight when compared to entire body mass.
- Option C: 80 to 90 mL/kg
This range is generally considered too high for dogs. It is more aligned with blood volume in other species but not typically dogs.
- Option D: 40% of their BW
This would suggest nearly half of the dog's body weight is blood, which is an overestimation. Blood volume in dogs is much lower in percent of body weight.
3. Determine the most accurate option:
Based on standard veterinary references and physiological data, dogs have a circulating blood volume of approximately 40 to 60 mL/kg.
### Conclusion:
The correct answer is:
A) 40 to 60 mL/kg.
