الفهرس 
.INTRODUCTIOOnly 14 pages are availabe for public view
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Abstract
Objectives of this thesis are studied the effect of feeding different levels of NRC (1975) requirements, i. e. 100, 85, 70% on productive and reproductive performance of ewes in addition, effect of lambs creep feeding during suckling period of ewes fed different levels of NRC (1975) on growth performance of lambs from birthing to weaning is studied . Moreover, estimation the time of resumption of estrous cycle after lambing and during suckling period in ewes fed different levels of NRC (1975) requirements with feeding their lamb’s further diet during suckling period also studied. Fifty four local Egyptian ewes (average 3-4 years old and average live body weight of 41.6 kg at lambing) were used in this study. Experimental ewes were divided after lambing directly into three equal groups (18 ewes each). The amount of feeds offered to ewes during the first eight weeks from lambing was 4.2, 3.57 and 2.94% DMI as a percentage of LBW for 100 and 85 and 70 %NRC for 1st , 2nd and 3rd groups, respectively, which contained 25:75 roughage concentrate ratio and the percentage of roughage were 15 % berssem and 10 % rice straw. Within each experimental group, ewes were divided into two equal subgroups. Lambs of the first subgroup were fed additional ration during suckling period through creep feeding, while in the 2nd subgroup; lambs were maintained without any additional ration. Rams were introduced to the three experimental groups of ewes after two weeks from lambing. Overall mea n of ALT activity, urea and creatinine levels were affected significantly (P<0.05) by creep feeding. Overall mean of total protein, albumin and globulin concentrations and progesterone and T3 levels as well as AST activity were not affected significantly by creep feeding. Due to creep feeding, overall mean of ewe milk yield, fat corrected milk yield (4%) (FCM), fat percentage and fat yield at different days after parturition were not affected significantly. While, percentages of total solids and solids not fat on day 60 after parturition were affected significantly (P<0.05) affected by creep feeding. Overall mean of total protein, albumin and globulin concentrations, T3 level and ALT, AST activities in ewes were affected significantly (P<0.05) by level of requirements. Overall mean of urea, creatinine and progesterone in ewes levels were not affected significantly (P<0.05) by level of NRC requirements. Percentages of ash, total solids and solids not fat in ewe’s milk were affected significantly by level of requirements on days 30 and 45 after parturition. No significant difference due to creep feeding and level of requirements in ewe’s body weights on different days after parturition. Lamb body weight gain at 4th two weeks from lambing was affected significantly (P<0.05) by creep feeding. Lamb body weight gain was affected significantly by level of NRC at 1st two weeks and 3rd two weeks from lambing. Ewes of lambs with creep feeding had a shorter period to resumption of estrous cycle from lambing than those of lambs without creep feeding. from this study, some levels of 85% NRC can be used for feeding in local ewes during suckling period, because it had good effects on production performance. Also, creep feeding of lambs should be used during suckling period because ewes with lambs fed creep had a shorter period to resumption of estrous cycle from lambing than those with lambs fed non creep.