A simple rule to prevent excess blood collection in an animal is to collect no more than what percentage of body weight as blood at one time?

Answer: 1%

Step-by-step explanation:

No more than 1% of the animal's body weight in one collection or over a 24 hour period

For example: 25g mouse x 1% = 0.25mL or 250uL maximum blood removal

No more than 1.5% of the animal's body weight in two weeks (14 days)