Here's why:
* Blood volume varies: Blood volume depends on the size and weight of the dog. A smaller Jack Russell will have less blood than a larger one.
* Individual differences: Even dogs of the same breed and size can have slightly different blood volumes.
* Health factors: Factors like hydration level and overall health can also affect blood volume.
It's important to consult a veterinarian if you have concerns about your dog's blood volume. They can perform tests and provide accurate information specific to your pet.