Measuring the heat loss in horses in different seasons by infrared thermography.

It is necessary to consider breed and cold tolerance in the housing and caring of horses. This study demonstrates differences in heat loss between horse types at low temperatures and examines rate of loss in different types during different seasons. Eighteen horses participated. Groups by type were light (L), warmblood (W), coldblood (C), and pony (P). A camera filmed thermographic images at 15 degrees C, 2 degrees C (all types), -8 degrees C (L, W, C), and -12 degrees C (P). The study calculated loss from the neck, trunk, and inner surfaces of front and hind legs. Loss was similar in all types at 15 degrees C. L, W, and C dissipated more heat at 2 degrees C than at 15 degrees C (p < .001) and from neck and trunk at -8 degrees C than at 2 degrees C (p < .05). P dissipated heat similarly at 2 degrees C and -12 degrees C. At 2 degrees C, loss was less from neck and trunk in C and P compared with L (p < .05). At -8 degrees C, loss in L and W was greater than in C (p < .05).