Ten adult Saladi bucks (2.5-3.5 years old and average live body eight of
36.5±0.87 kg) in addition to 10 Syrian Gabali bucks (2.5-3.5 years old an average
live body weight of 40.5±0.57 kg) were used to compare their thermo-respiratory and
cardiac responses (0 tree sheltering during summer season. Each breed group was
divided Into two sub-groups (5 each). The first sub-group of each Saladi a d Gabali
bucks was kept under tree natural sheltering (Casurina equistifolia) while t e second
sub-group was left unsheltered in wire-fenced pens along day and night ~uring the
experimental period from July to September, 2000. Thermo-respiratory p~rameters
(rectal temperature (RT), respiration rate (RR), skin temperature ~.sT), coat
temperature (CT) and different temperature gradients (RT-ST, ST-CT, RT-Cir and RT-
AT) were recorded once weekly twice a day at 08.00 hr and 14.00 hr. I addition,
plasma and blood volumes, plasma proteins, potassium, sodium and a dosterone
hormone were also determined. Results revealed that the tree sheltering tempered the thermal C9nditions of
the microclimate particularly radiant ambient temperature. Sheltered groups had
more limited diurnal increases of RT (0.45 VB. 1.10 0q, RR (9.6 VB. 41.0 breaths/min),
ST (0.7 vs. 2.6 0c), CT (0.5 vs. 2.7 0c) and heart beat (8.4 vs. 29.5 beats/min) as
compared with unsheltered ones. Consequently, both Saladi and Gabali b cks would
be more heat tolerant by tree sheltering during the hot period of the day. Sody-
environment temperature gradi~nts (RT-ST, S.T-~T and RT-CT) w~re also eiscussed. Summer heat stress. did not affect significantly hematocnt value, hemoglobin
concentration, plasma protein levels and albumin/globulin ratio for eittier Saladi or
Gabali goat bucks. Plasma and blood volumes and their percentages from body
weight lended to increase inSignificantly in heal stressed groups. Without sheltering,
plasma concentrations of aldosterone hormone, sodium and potassium decreased by
29, 8.8 and 15.8% for Salad! bucks and 35, 10.3 and 13.5 % for Gabali bucks,
respectively. The present results indicated that sheltering might act as emperature
regulator for the microclimate and in turn for body temperature of shelle ed animals.
Also, under heat stress conditions Gabali bucks were more able to sustain their
thermal balance with less physiological efforts, so they seemed to be ore adapted
rather than Saladi bucks under semi-arid conditions.