Observations on the effects of vibration stress and sound on pregnancy, parturition and respiration in the rabbit.

Rabbits, 5-29 days pregnant, were placed for 2 h either in or near a machine designed to simulate transport, which exposed them to vibration stress and sound. There was no apparent effect on the maintenance of pregnancy, gestation length, litter size, perinatal mortality or condition of the young at birth compared with control rabbits. However, respiration rate, normally 65/min, was increased to 120/min by moving the animals from their cages and to 160/min in the machine; noise alone produced an intermediate response. Respiration returned to normal values after 20 min to 4 h, depending upon the initial level of response.