No effect of week on hourly AMBT measurements
from iButton temperature loggers fi xed in the stall area
(shade) or exercise area (sun) was observed; therefore, the
mean AMBT at each time point during exercise was reported.
Ambient temperatures to which the stallions were
exposed differed (P < 0.0001) during the exercise protocol,
as stallions were moved from the shaded stall area at
0 min to the heat of the sun at 22 and 30 min and back
to the shaded stall area at 60 and 120 min postexercise.
Mean AMBT increased 9.8°C (P < 0.0001) from 34.6°C
at 0 min of exercise and 60 and 120 min post-exercise to a
peak of 44.4°C at 22 and 30 min of phases I to III. A slight,
but insignifi cant, decrease (P = 0.43) in mean HUM was
observed between exercise time points.