Cocks were exposed to 1 or 2 h at 24 degrees C; blood samples were taken before and immediately after treatment and for a period of 20 h thereafter. 2. Heat caused a significant decrease in leucocyte counts, an increase in corticosterone concentration in plasma and an increase of ascorbic acid in plasma and in leucocytes. 3. These four measures can be used to indicate a stress response and the measurements can be done without harming the animal.

SUMMARYThe effect of 1 hour exposure of seven 1-week-old chicks to heat stress (41.5-42.5°) on their antibody titre after antigenic stimulation with E.coli bacteria was assessed.Exposure to heat 24 or 96 hours after immunisation resulted in a significant increase in antibody titres while heat treatment 42 or 72 hours after vaccination caused a non-significant increase in antibody titres. Heat exposure for 2 hours, 24, 48, 72 or 96 hours after immunisation either with E. coli or sheep red cells (SRBC) resulted in significantly increased antibody titres. When a number of antibody forming cells (against SRBC) in the spleens were tested, heat treated chicks showed no significant increase compared with the non-treated group. Heat-exposed chicks phagocytised Staphylococcus aureus bacteria (as measured by their disappearance from the blood) more rapidly than the non-treated group.

No abstract

No abstract