الفهرس 
Structure of somatotropin
Effect of parityOnly 14 pages are availabe for public view
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Abstract
This study was carried out at Mahlet Mousa Research Station during the period from April 2001 to December 2003.A total of 76 buffalo cows was used in this study, 40 in the 1st experiment, with different parities (25 lactation<U+2019>s). In the 2nd experiment buffaloes were used in this experiment, 10 of each were primiparous and the other 10 were muItiparous lactating buffaloes (35 lactation). In the third experiment 16 buffaloes in 3rd experiment. In experiments animals were divided into two nearly similar groups (control and treated). All treated buffaloes were injected subcutaneously with 500 mg rbST, at injection intervals of 14 days for 10 injection. The objective of this work was to: (1) investigate the effects of treating buffaloes with rbST on milk yield and milk composition of Egyptian buffaloes; (2) to study the effects of using rbST on physiological and biochemical changes of buffaloes blood that occur along the lactation ; (3) to study histological changes, if any, that may occur in the buffalo mammary gland in the first lactation in response to rbST treatment; (4) to investigate the effects of using rbST on the postpartum reproductive performance of buffaloes, and (5) to evaluate the economic efficiency of using rbST for increased milk production. The results obtained can be summarized as the following: Milk production: The total milk yield, lactation period length and average daily milk yield were affected significantly by rbST treatment. However, milk yield pre and posttreatment period did not differ significantly between treated and control groups. Milk composition: Fat yield during treatment and total fat yields during the whole lactation period were significantly higher in the treated than the control group. However, fat percentage pre, during, and posttreatment and fat yield pre and posttreatment did not differ significantly between the two groups. Percentage and yield of milk protein during treatment and the whole lactation period were significantly higher in the treated than the control group. Reproductive performance: There was no significant differences in reproductive performance between treated and control group. No significant effect for injection of rbST on live body weight pre, during, and post treatment between treated and control group. The histological changes in the mammary alveoli were associated with increasing milk yield without significant changes in milk contents as affected by rbST treatment. The primiparous buffaloes showed highly response to rbST than multiparous buffaloes. Concentrations of TP, AL, GL and glucose, and activity of GOT and GPT in blood plasma were affected significantly by rbST treatment. 4.2 Effect of rbST was significantly increase concentration of insulin and T3, while concentration of T4 was not affected significantly by rbST. The economic analysis conducted that use of rbST would be profitable for both high and medium producers and primiparouse buffaloes and is not for low producers under same condition.