# Policy on Blood Withdrawal Volumes and Frequency of Collection of Blood from Research/Classroom Animals

## Body Weight

As a general rule, approximately 7.0% of an animal's body weight is comprised of blood.

Examples:

• 10 lb (4.54kg) rabbit: 7.0% of 4.54 kg = 0.31 kg = 318 ml
• 40 g mouse: 7.0 % of 40 g = 2.8 g = 2.8 ml

## Total Blood Volume

As a general rule, 15.0% of an animals total blood volume can be safely removed without severely harming the animal (of course fluid replacement therapy must be instituted if this maximum volume is removed)

Examples:

1. 10 lb (4.54 kg) rabbit: 7 % of body weight = 318 ml; 15 % of 318 ml = 48 ml
2. 40 g mouse: 7% of body weight = 2.8 ml; 15% of 2.8 ml = 0.42 ml

## Blood Loss

As a general rule, animals will replace lost blood at a rate of 1 ml per pound body weight per 24 hours (1ml/lb/24hr)

Examples:

1. 10 lb rabbit will produce 10 ml of blood in 24 hours, 20 ml of blood in 48 hours, etc.
2. 40 g mouse will produce 0.08 ml of blood in 24 hours, 0.16 ml of blood in 48 hours, etc.

## Replacement

Animals cannot be bled at a volume and frequency that does not allow them to replace their blood volume.

Example:

• 10 lb (4.54 kg) rabbit: if 50 ml of blood is drawn (maximum safe bleed) this amount cannot be taken again for another 5-7 days (1 ml/lb/24hr at 10 lb = 5 days)

Questions concerning blood withdrawal from animals should be directed to Tracy Dolan, Research Facilities Coordinator (x 55483) or Dr. John Young, University Attending Veterinarian (310-423-7684).

Rev. 5/01