الفهرس 
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Abstract
V. SUMMARY AND CONCLUSION
The present study was carried out at the Experimental Research Station located in Shalakan, El-Kanater El-Khaireia belonging to Animal Production Department, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.
The aim of this study was to assess the influence of housing system and pregnancy on some physiological parameters including rectal temperature, respiration rate, biochemical profile of blood plasma, lamb growth and mortality rates during lactation period, changes in plasma progesterone and leptin concentrations during late pregnancy and early lactation and changes in milk leptin and milk components during 12 weeks of lactation.
Twenty Ossimi ewes, with average body weight 40-45 kg and in the third breeding season, were used in this study. Animals were divided equally into two groups, each group included 6 pregnant and 4 non-pregnant ewes. All pregnant ewes were in the 4th month of gestation. The first group was maintained in the confined housing system while the second group in the loose housing system. Blood sampling was performed weekly during the last seven weeks of gestation and the first five weeks of lactation.
The results obtained in this study could be summarized as follow:
1. Mean rectal temperature of ewes was higher in the confined than in the loose housing system by about 1°C, and this increase in rectal temperature was not significant.
2. Mean respiration rate of ewes during the period from November to March increased (p<0.05) in the confined than in the loose housing system (40 vs. 33 breath/min)
3. Housing system had insignificant effects on all blood parameters studied except hematocrit value and plasma glucose. Loose housing system increased hematocrit value and decreased plasma glucose level significantly.
4. Pregnant ewes were significantly (p<0.01) higher in hematocrit, plasma glucose, creatinine, AST, ALT, progesterone and leptin while had no significant effects on the levels of blood proteins compared to the corresponding values in nonpregnant ewes.
5. Milk protein, fat and lactose were not significantly influenced by housing system, however, milk protein and fat tended to increase in the loose compared to the confined housed group probably due to daily berseem grazing which was not allowed for the confined housed group.
6. Milk protein, fat and lactose were significantly influenced by week of lactation. Milk protein and fat exhibited a gradual decrease with advancing weeks of lactation, while milk lactose did not show similar trend.
7. Lamb birth weight was not significantly influenced by housing system while weaning weight was significantly (p<0.05) higher in the loose than in the confined housing system (23.5 vs. 19.7 kg).
8. Daily gain of lambs during lactation period was significantly (p<0.01) higher under loose housing system compared to the other housing system (244 vs. 201 g/day).
9. Mortality rats of lambs during suckling period was 37.5% in the loose and 16.6% in the confined housing system. More lambs died during the first week of age in winter probably due to night cold stress and low body weight under loose housing system.
10. Plasma progesterone concentration was significantly (p<0.05) influenced by weeks of late gestation and early lactation but not influenced by housing system. Plasma P4 sharply decreased at parturition and started to increase after one month of lactation indicating resumption of estrous cyclicity in ewes.
11. Plasma leptin was significantly (p<0.05) influenced by week of late gestation and early lactation but not influenced by housing systems. Commencing from week 19 of gestation plasma leptin gradually decreased till the first week of lactation then little increase occurred thereafter.
12. Plasma progesterone concentration was significantly (p<0.01) correlated with leptin during late gestation but not during lactation.
13. Milk leptin was significantly (p>0.01) influenced by week of lactation and housing system, and there was an interaction between both factors.
14. There was a gradual increase in milk leptin during the first five weeks of lactation followed by a gradual decrease till the end of lactation.
15. Increased growth rate and daily gain of lambs in the loose housing system may be regarded to the significant increase of milk leptin, beside higher levels of milk fat and protein, compared to confined housing system.
16. In conclusion, loose (outdoor) housing system for ewes seems to be better than confined (indoor) housing system, but animals under loose housing system require greater energy for maintenance and locomotive activity.
In addition, blood leptin may enhance fetal growth, synergistic with progesterone, during pregnancy while milk leptin may promote initial growth of suckling lambs. These points of view need further investigations.