Comparative studies on heat tolerance in ponies and donkeys.

摘要

The effects of exposure to direct sunlight for 6 h on 6 consecutive days were studied in India in 5 local donkeys, 3 Italian donkeys, and 3 local Malani ponies. Respiration rate and rectal temperature were recorded in the morning and evening of these days, as well as on the 6 preceding days, and the 2 following days, when the animals were kept inside in a semi-open shed. Heat exposure caused a significant increase in respiration rate, particularly in the Italian donkeys and local ponies. Rectal temperatures varied in the 3 groups in the pre-exposure period, but increased significantly in all groups in the afternoons during exposure. The maximum increase was in the Italian donkeys (to 39.11±0.14deg C), and the minimum in the local ponies (to 38.39±0.12deg C). The local animals appeared unable to reduce their body temperature during the low temperature respite overnight, but in all groups body temperature decreased to pre-exposure levels in the 2 days after exposure.