الفهرس 
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Abstract
Two experiments were conducted to evaluate the effect of br administrating melatonin, ZADO and their combination on reproductive br performance of Ossimi ewes in the first experiment and ZADO br supplementation effects on milk yield and lambs growth in the second br experiment. Exp.I. fifty-seven, multiparous, adult Ossimi ewes were br randomly assigned to four groups, each group fed ration supplemented br with one of the following components: melatonin (G1; n = 14), ZADO br (G2; n = 14), melatonin and ZADO (G3; n = 15)and ration with no br additives (G4; n = 14). All ewes were fed maintenance ration for one br month (during June) followed by flushing ration for five weeks (two br weeks before and three weeks after ram introduction). Melatonin br (3mg/h/d) and ZADO (15g/h/d) started to be added with maintenance and br flushing rations, respectively. Fertile rams were introduced for two br successive estrous cycles. Percentage of ewes expressed estrus was br significantly different (P -lt; 0.05) among the treatment groups. All ewes br expressed estrus in G1, while the lowest percentage (71%) was detected br n G4. The interval -#102;-#114;-#111;-#109; ram introduction to the onset of estrus differed br (P -lt; 0.01) among treatment groups. Ewes received melatonin in G1 and br G3 expressed estrus earlier than ewes didn’t receive melatonin in G2 and br G4. Neither body weight nor body condition score were different at the br first estrus following ram introduction, while average daily gain (ADG)was promoted by treatments particularly melatonin, but the difference br was not significant. Lambed ewes as percentage of total ewes were br similar in G3 and G4 (50%), while they increased in G1 and G2 (57 and br 67%, respectively). Prolificacy was greater in G1 and G3 than that in G2and G4. Maximum prolificacy was detected in G3 while the minimum br was observed in G4, the difference was significant (P-lt;0.01). Fecundity br was lower (P -lt; 0.01) in G4 (control group) than all the treated groups br (G1, G2 and G3). Results of the present study indicated that melatonin br could increase the estrus expression of ewes and decrease the interval to br estrus after ram introduction. Exp. II twenty recently lambed Ossimi ewes br were used with their offsprings in this experiment. Ewes were equally br divided into two groups (ten ewes in each). Group 1 was supplied with 10 br g/head/day ZADO mixed with total ration, while group 2 had the same br ration with no additives and served as control. The average daily milk br yield (DMY) was 907 vs. 787 g and weaning weight was 17.46 vs. 15.20 br kg for ZADO supplemented and control groups, respectively. Melatonin br alone or in combination with ZADO could increase prolificacy. Treated br ewes with melatonin and/or ZADO could improve fecundity. ZADO br supplementation could improve DMY and lamb weight at weaning.