Corticosterone, adrenal and spleen weight in mice after tail bleeding, and its effect on nearby animals.

Experiments were performed in mice to study if stress was involved in tail bleeding and to investigate any transmittable signal at killing. A second study looked at the time taken to recover from stress elicited by these procedures. Corticosterone levels were significantly higher in mice immediately after the completion of tail bleeding than in control mice (P < 0.05) suggesting that tail bleeding in mice was stressful. This study did not show any evidence for an odour or sound being released during killing or tail bleeding as there was no significant effect on corticosterone levels in mice present in the same room at the time these procedures were carried out. Corticosterone levels in mice killed on days 1, 3, and 7 after tail bleeding were significantly lower (P < 0.05) than the average corticosterone level in tail blood on day 1, indicating that mice recovered within 24 h from the stress of tail bleeding.