The relationship between the hair cycle and the age or daily body weight gain in rabbits.

The relationship between the hair cycle and the age or daily body weight gain (daily gain) in rabbits was investigated. A survey of the ages of rabbits used for the dermal toxicological studies in our laboratories over the last 4 years was done, followed by an experiment to confirm the results of the survey. Although there seemed to be no relationship between the hair cycle and the daily gain, the results showed that the hair cycle was closely related to the age of the animal, and the animals in the telogen stage may be obtained efficiently at about 17 wks of age.