An experiment was carried out on 36 growing Barki lambs 10 study some
physiological responses as affected by two housing systems (semi-closed and dosed)
in comparing with unshaded one along four successive seasons. The lambs average
age and weight were about 6 months and 23 kg respectively at the start of the
experiment (winter season). Climatic conditions were recorded simultaneously when
measuring physiological traits two times a day at 06.00 and 14.00 h biweekly
intervals. The studied physological responses were respiration rate (RR). rectal
temperature (RT). Skin temperature (ST). water consumption 0/V.C.). cell blood
counts (RBC and WBC). haematocrft (PCV) and haemoglobin (Hb). The results obtained showed significant diurnal and seasonal variations for all
parameters studied exoept the diurnal for (Hb). Shaded pens had lower ambient
temperature AT (non Significant). solar radiation SR (signi6cant) and higher relative
humidity RH (significant P greater in dosed pens than in the semi-closed in comparison with the unshaded.
Whereas the increase RH was high in closed pen than semi-closed in comparison
with the unshaded. RR, RT and 5T were Significantly lower under shaded pens during
fou~ seasons except ST was high in cold winter season indicating that shading helped
in warming the animals RR, RT and 5T were significant +ve and -ve correlated with
AT and RH respectively. Closed system imposed heat stress on the animals within. it increased water
consumption during hottest periods with larger degree than what occurred in semi-
dosed than unshaded animals. Generally shading helped in saving W.C. Body weight
was not signifICantly affected by housing types although the animals in the semi-
closed had higher body weight than those in the other two types. Shading helped in
an significant increase (P kept wec at constant and high level than other two pens (dosed and unshaded)
along the experimental study.