الفهرس 
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Abstract
The present study was planned to investigate the valueof biochemical parameters as indicator traits for genetic improvement of milk and fat production in buffaloes. Accordingly, non-genetic causes of variation were traced firstly, then appropriate genetic analyses were performed to estimate the heritability and repeatability coefficients for serum and production variables as well as phenotypic and genetic correlations among them. Also, breeding values were calculated to provide genetic ranking of sires for gelection purposes. Moreover, different regression models were tried in an attempt to provide prediction equations for milk and milk fat using the levels of blood metabolites and thyroid hormones.
Statistical analyses were executed on serum metabolic profiles and production variables of 93 lactating Egyptian buffalo cows belonging to Animal Production Research Institute. Traits studied were milk yield, fat yield and fat percentage. In addition to serum levels of thyroxine (T4), triiodothyronine (T3), total protein (TP), albumin (AL), globulin (GL), urea, cholesterol (CH), triglycerides (TRI), alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), calcium (Ca) and phosphorus (P). Also, ratios of thyroxine to triiodothyronine (T4 : T3), albumin to globulin (AGR) and calcium to phosphorus (Ca: P) were included.
rhe following results were obtained:
Relatively high values for milk yield (7.55 kg/day), fat yield (431.09 g/day), and moderate fat percentage (5.92%) were obtained in the present study compared to those reported in previous investigations on Egyptian buffaloes. In addition, the metabolic profiles ranged mostly within the intervals of the cited literatures