الفهرس 
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Abstract
This study was conducted on 15 Friesian cows with 4-6 year of age (450 – 600 kg, body weight). Animals were divided randomly into three groups (5 cows in each). Cows in 1st experimental group were fed according to NRC (2001) requirements for dairy cows, and the diet was contain concentrate feed mixture (CFM), 2nd cut of berseem (Trifolium alexandrinum), and rice straw (RS) without any treatment as control. Cows in the 2nd experimental group were fed the same ration of control group, and injected intramuscularly with 5 ml Gn-RH (Receptal®, a Gn-RH agonist, Hoechst Canada, Regina, SK, Canada) after the occurrence of uterus symmetry while, the non-responded cows were received the same dose of Gn-RH every 11 days. Cows in the 3rd experimental group were fed the control ration, and supplemented with 3% protected fat on dry matter basis (375 g/d/h, MEGALAC®, a calcium soap of palm fatty acids; Volac Ingredients Sdn. Bhd., Pasir Gudang, Malaysia) after calving. The CFM were content of uncorticated cotton seed cake(65%), wheat bran(9%), rice polish (20%), molasses (3%), limestone (2%) and NaCl (1%). Water and mineral blocks were available all day. The feeding period lasted from the day of calving to 90 days postpartum. The obtained results could summarized as the following:- to evaluate the effect of hormones or dry fat treatment on postpartum lactating cows reproductive performance. The experimental period was lasted from calving to 90 days postpartum. 1- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow reproductive performance: The results showed significant (P˂0.05) effect for treatment with Gn-RH or dry fat supplementation on symmetry of uterine horn and days open, while the different treatment groups did not affected significantly on fetal membrane drop, first estrus or number of service per conception. The interval from calving to symmetrical of uterine horns occurred early significantly (P˂0.05) in G3 and moderated in G2 and G1 was tardily. In addition, days open were significantly (P˂0.05) the shorter in G3 flowed by G2, while, G1 showed the longer period. 64 Data indicated non-significant effect for Gn-RH treatment on the interval from calving to first postpartum estrus occurs being early by 11.1% than G1, and was later by 1.7% in G3 than G1. In this respect, the dry fat treatment (G3) showed non-significant decrease in number of service per conception (by 0.8 services) compared to G1 (control) and Gn-RH treatment showed also non-significant decreased by 0.2 services, in the same order. 2- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow blood concentration of P4 and E2 after calving: The results showed significant (P˂0.05) increase in blood P4 concentration in G3 compared with G1 and G2, being high by 61.8% than G1 and 39.8% than G2. Results indicated significant rise in dairy cow blood E2 levels in G3 as affected by dry fat treatment compared to those in G1 and G2 by about 18 and 14%, respectively. Data of G3 indicated a sharp upward in P4 concentration start from the 60d sample which reflect that there were 4 cows had DO less than 60 days and only one cow had more than 75 days as DO period. Data of E2 levels in dairy cows blood samples showed clear increased in G3 at 45d PP sample, which reflect the presence of four cows conceived from the first service and it showed estrus above this sample time. 3- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow blood biochemicals: 3-1- Total protein and its fractions: Results indicated that by day 15 postpartum, TP concentration did not differ significantly in different treatment groups, but after 30 days of parturition, it was increased significantly (P<0.05) in G3 as affected by protected fat than both of G1 or G2. At 60d postpartum period, G3 showed the high value of TP followed by G2 and finally G1. As affected by treatments G3 and G2 showed the high values of TP compared to G1. 65 In general, data showed significant effect (P<0.05) for GnRH and dry fat treatments on both total protein and albumin concentrations in dairy cow blood, being highly significant (P<0.05) in G3 (dry fat) followed by G2 (GnRH) compared to control group (G1) for total protein. In addition G3 showed the high significant (P<0.05) effect on blood albumin concentration followed by G2 in compared to G1. While, the concentration of blood globulin did not showed any significant differences (P<0.05) between different treatment groups. The results of AL concentrations in blood plasma of cows in different experimental groups reveled that there is a significant (P<0.05) increase in G3 and G2 than G1 at 30, 60 and 90 days postpartum. Data showed that no significant (P<0.05) differences were found between treatment groups in GL concentrations of cows blood plasma at 15, 30, 60 and 90 days postpartum. 3-2- Lipid profiles: The present study results of the concentration of blood TL, TG and Chol showed no significant (P<0.05) differences between experimental groups as affected by treatment at different experimental periods. Data clearly showed a significant effect (P<0.05) for protected fat supplementation (G3) on blood TL concentrations among experimental period starting from 30 days postpartum than remain experimental groups (G1 and G2). The positive effect of protected fat supplementation on blood TL in G3 appeared clearly in the increase in G3 values by 46.0 and 32.6% than G1 and G2 at 30 days postpartum, and by 24.2 and 15.3% at 60 days postpartum, and 48.5 and 42.8% at 90 days postpartum, in the same order. The overall mean of total lipids as affected by different treatment groups indicated high significant effect (P<0.05) for G3 followed by G2 and in the final G1. Concerning the effect of different treatments data indicated significant increase (P<0.05) in G3 than those in G1 and G2, being the highest significantly (P<0.05) in G3 followed by G2 then G1. The percentages of increase in G3 than G1 66 and G2 were 9.3 and 8.4% at 30 days postpartum, 18.7 and 17.2% at 60 days postpartum and 22.8 and 21.9% at 90 days postpartum, respectively. Results showed a significant effect (P<0.05) for dry fat treatment on the overall concentration of blood triglycerides of dairy cows in G3 compared to G2 or G1. It is clear to note that, data showed the similar trend for blood cholesterol, being the highest value for G3. The concentration of Chol in G3 was higher by 23.4 and 18.5% than G1 and G2 at 30 days postpartum, and then this trend of improve increased to be 38.4 and 20.7% compared to the same groups at 60 days postpartum. In addition, at 90 days postpartum the improvement percentages were 30.1 and 19.5%, in the same order. Overall mean of blood cholesterol concentration of dairy cow indicated highly increased (P<0.05) in G3 compared to those in G1 or G2. 3-3- Glucose concentration: Data showed no significant differences (P<0.05) between experimental groups at 15 days postpartum in the concentration of glucose. While, the significant increase (P<0.05) was found in blood of cows supplemented with protected fat (G3) at 30, 60 and 90 days postpartum while, G2 showed the moderate values at the same periods compared to control cows (G1). Results showed that glucose concentration in blood of dairy cows in G3 was highly significant (P<0.05) and moderated in G2, while, G1 showed the low concentration. 3-4- Liver function indicators: Results of the activity of AST and ALT showed no significant differences (P<0.05) were found in different experimental groups at 15 days postpartum. The levels of AST showed liner decrease started from 30 to 90 days postpartum in G3 (protected fat) compared to remained groups (G1 and G2) and it showed (G3) significantly (P<0.05) the lowest values compared with G1 or G2. The values of AST in G3 were decrease among the experimental period by 58, 50 and 69% compared than control at 30, 60 and 90 days postpartum, respectively. 67 Data showed significant differences (P<0.05) between different experimental groups. The lowest value of AST was in G3 followed by G2 and the highest value being in the control group (G1). As affected by different treatment groups, ALT showed low significant (P<0.05) values in both groups G2 and G3 compared than G1. The lowest value of ALT was recorded in G3 at 30 days postpartum, being low in G3 by 72.8% than G1 and 54.5% for G2. In this respect data showed that, G3 was low than G1 by 42.8% at 60 days postpartum, also, G2 was low by 38.9% than G1 in the same time. At 90 days postpartum period, G3 and G2 showed low values for ALT level than G1 by 55.3 and 53.2%, respectively. As affected by treatment group, the concentration of ALT was low significantly (P<0.05) in G2 and G3 compared to the high value in G1. 3-5- Creatinine concentration: The present results of the concentration of blood creatinine showed significant (P<0.05) decrease in cows of G3 than either G1 or G2. Data indicated that G3 was decrease by 30.8, 22.1 and 39.6% than G1 at 30, 60 and 90 days postpartum, respectively. In addition, there is a significant decrease in the concentration of creatinine in G3 by 32.1, 16.7 and 37.9% than in G2 at 30, 60 and 90 days postpartum, respectively. Data showed significant decreased (P<0.05) in creatinine concentration as affected by dry fat treatment in G3 compared with the remain groups (G1 and G2). 4- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow glutathione activity in blood: Results showed no significant (P<0.05) differences between the experimental groups in glutathione concentration at 15 days postpartum. Data indicated that G3 had the high concentration of glutathione followed by G2 and finally G1 at 30, 60 and 90 days postpartum periods. The highest value of glutathione concentration was recorded in G3 at 90 days postpartum, while the lowest one was in G1 at 30 days postpartum (Table, 14). 68 Concerning the effect of treatment group on the concentration of glutathione, results showed significant increase (P<0.05) in G3 and G2 compared to G1. 5- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow immune response: 5-1- Concentration of immunoglobulin type G: Results showed the effect of different treatments on the concentration of cows blood plasma IgG. In spite of no significant (P<0.05) differences were found between experimental groups at 15 days postpartum period, however, IgG recorded the lowest value at this period compared to the remain experimental periods. The results indicated that, IgG concentrations in G3 were higher significantly (P<0.05) by 9.4, 13.6 and 20.3% than G1 at 30, 60 and 90 days postpartum, respectively. The concentration of IgG was affected significantly (P<0.05) by treatment group, the data showed that G3 had the higher concentration and G2 showed the moderated concentration while, G1 showed the lower concentration. 5-2- Concentration of immunoglobulin type M: The results indicated the same trend for IgM as presented for IgG. Data showed that among experimental groups there were no significant (P<0.05) differences found in IgM concentration at 15 days postpartum. While, G3 showed that the concentration of IgM were increase significantly (P<0.05) by 34.6, 76.3 and 43.5% than G1 at the followed experimental periods (30, 60 and 90 days postpartum, respectively). The data of IgM concentration showed the same trend of IgG being the higher in G3 and moderated in G2 while, the lower concentration was in G1. 6- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow hematological parameters: 6-1- Count of white blood cells: The present study showed that at 15 days postpartum there were no significant (P<0.05) differences found between different experimental groups in WBCs count. Results reflected a significant (P<0.05) increase in the count of WBCs in G3 compared to G1, while, G2 showed the moderated value. WBCs count increased significantly (P<0.05) in G3 by about 46% than G1 at 30 and 90 days postpartum, while at the 60 days postpartum the increase rate was 55.3%, in the same order. Data showed significant increased (P<0.05) in the overall mean of white blood cells count as affected by dry fat treatment in G3 and G2 showed the moderated value as compared to G1. 6-2- Count of red blood cells: The presented data showed no significant (P<0.05) differences found in RBCs count between different experimental groups at 15 days postpartum, while, at 30 days postpartum there is a significant (P<0.05) increase in G3 compared to G1 or G2, the percentage of increase rate related to G1 was 26.7%, and to G2 was 22.9%. At 60 and 90 days postpartum periods, the count of RBCs in G3 showed the highly significant (P<0.05) value and G2 showed the moderated value, while, G1 showed the low value. 6-3- Hemoglobin concentration: Results showed that no significant (P<0.05) differences were found between the experimental groups at 15 days postpartum, while, G3 achieved the high significant (P<0.05) concentration of hemoglobin as compared to G1 from 30 days postpartum until the end of experimental period. Only at 90 days postpartum, there were a significant difference found between G3 and both experimental groups G1 and G2. As affected by treatment groups the blood hemoglobin showed high significant concentration (P<0.05) in G3 and moderated in G2 and the low was in G1. 6-4- Packed cell volume percentage: Data indicated that, at 15 days postpartum period no significant (P<0.05) differences were found between the different experimental groups. from 30 days postpartum until 90 days postpartum, G3 recorded the highly significant (P<0.05) percentage of PCV and G2 showed the moderated percentage while, G1 showed the low percentage. The overall mean of packed cell volume percentage in dairy cows blood was affected significantly (P<0.05) by dry fat treatment in G3 compared to GnRH treatment in G2 or non-treated in G1. 70 7- Effect of hormonal treatment or dry fat supplementation on Friesian dairy cow milk production and constituents: 7-1- Milk production: The data showed insignificant (P<0.05) increase in monthly milk yield in G3 followed by G2 and finally G1. At 60 days postpartum, monthly milk yield in G3 increased by 39.7 and 43.1% than G1 and G2, respectively. Also, at 90 days postpartum G3 increased than G1 and G2 by 34.1 and 33.9%, respectively. In the respect of effect of experimental groups on dairy cow daily milk yield, data showed insignificant improve in G3 followed by G2 and in the final G3. At 60 and 90 days postpartum, results showed a significant (P<0.05) increase in daily milk yield of cows in G3 than both G1 and G2. The overall mean of monthly milk yield of dairy cows was increased significantly (P<0.05) in G3 compared to G2 or G1. Data indicated that the overall mean of average of daily milk yield of dairy cows recorded the high significantly (P<0.05) value in G3 followed by G2 then G1 and the differences between G1 and G2 were insignificant. 7-2- Milk constituents: The results of milk constituents including milk fat, protein, lactose ash, total solids (TS) and solids not fat (SNF) percentages showed that at 30 days, postpartum all the milk constituents did not affected significantly by different experimental groups. In this respect, G1 showed some increase but non-significantly (P<0.05) for the percentages of milk protein and SNF, also, G2 showed the same trend for milk fat percentage, and in G3 it was for milk lactose, ash and TS percentages. At 60 days postpartum the percentage of milk fat was higher significantly (P<0.05) in G2 followed by G3 compared by G1. In addition, at 90 days postpartum milk fat percentage in G3 showed the significant (P<0.05) high value and the moderate value in G2 and the low one in G1. The overall mean of dairy cows milk fat percentage showed significant increased (P<0.05) in G2 and G3 than in G1. Results showed significant (P<0.05) increase in milk protein in G1 compared by both G2 and G3 at 60 and 90 days postpartum. The percentage of protein in milk produced by cows in G1 increased by 0.58 and 0.69% than G2 and G3, respectively at 60 days postpartum, and at 90 days postpartum the same trend was found for G1 (by 71 0.71 and 0.64%, in the same order). The results of dairy cows milk protein percentage showed clearly significant (P<0.05) decreased in G2 and G3 compared to G1. Data showed that there were no significant (P<0.05) differences found in milk lactose percentage between different experimental groups in the present study among all experimental periods. In this respect G3 showed slightly insignificant (P<0.05) increase than the remaining groups (G1 and G2) at 30 and 60 days postpartum. Regarding to the presented data the milk ash percentage of cows in different groups did not affected significantly (P<0.05) by treatment at 30 or 60 days postpartum, while, at 90 days postpartum there is a significant (P<0.05) decrease in G3 than G2, while, G1 showed the moderate ash percentage. Data showed no significant differences (P<0.05) were recorded in the overall mean of dairy cows milk lactose percentage. Data showed no significant (P<0.05) effect for different treatment groups on cow milk total solids percentage at different treatment periods. Results of overall mean of dairy cows milk ash were showed insignificant effect (P<0.05) for different treatment groups on the milk ash percentage. The results of milk solids not fat percentage of cows in different treatment groups showed that the different groups did not affected significantly (P<0.05) on cow milk total solids percentage at 30 or 60 days postpartum. At 90 day postpartum, there is a significant (P<0.05) decrease in milk total solids of G3 than G1 and G2 showed the moderate percentage. The data showed significant decreased (P<0.05) in the overall mean of dairy cows milk solids not fat percentage in G2 and G3 compared to G1. The overall means of somatic cell count (SCC) in cow milk in different experimental groups data reflected that SCC was not affected significantly (P<0.05) by experimental group at 30 days postpartum, while, at 60 and 90 days postpartum there were significant decrease in G3 than in G1, while G2 showed the moderate SCC. Data indicated significant decreased (P<0.05) in the overall mean of dairy cows milk somatic cell count in G3 compared to G2 or G3. 72 In conclusion, The obtained results could be indicate that there are a significant (P˂0.05) effects for treatment with Gn-RH or dry fat on uterine horns symmetry and days open while, the interval from calving to symmetrical of uterine horns occurred early (significantly at P˂0.05) in G3 and moderated in G2 and G1 was tardily. The concentrations of total lipids, triglycerides, cholesterol and glucose in blood of lactating cows treated with protected fat were higher (P˂0.05) than control or Gn-RH cows, while, AST, ALT and creatinine were decreased (P˂0.05) which indicate that, cows treated with protected fat were in good nutritional status that make their liver and kidney in normal health with significant improved in all hematological parameters. from the obtained results it could be concluded that the treatment of lactating cows with 375 g/d/h of dry fat had positive effects on reproductive performance and blood biochemical and hematological parameters.