الفهرس 
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Abstract
The present study was conducted on a commercial herd with a stock population of 730 Holstein Friesian dairy cattle. On the farm, there were 170 cows at different stages of lactation. Only twenty four cows were located at a late gestation period. Blood samples were collected from these transition cows to estimate serum levels of BHB. Cows with no remarkable clinical signs but having serum BHBA concentrations > 1.20 mmol/L to 2.9 mmol/L were considered to have SCK (n = 20). At the meantime, cows with no clinical signs and serum BHBA < 1.00 mmol/L were considered to be negative controls (n = 4). All investigated cows were sampled twice: once at the initial screening of the transition cows (three weeks before the expected time of parturition and before initiation of treatment) and second at three weeks following calving i.e. after accomplishing the supplementation. Only clear non-haemolysed sera were collected and then aliquoted for estimation of BHB, NEFA, glucose, insulin, cortisol, MDA, SOD, triglyceride, cholesterol, ALT, AST, total protein, albumin, globulin, blood urea, creatinine, and VLDL. Tubes containing whole blood were used for hematologic examinations. Following the initial screening, cows with SCK were randomly assigned to receive RPN, (RPN – group; n = 5); CLO (CLO-group; n = 4), RPC, (RPC - group; n = 7); while the fourth group received no treatment and were then kept as a positive control (SCK – group; n= 4). Cows that have had normal serum BHB concentrations < 1.00 mmol/L were also enrolled in this study and were considered to be negative controls (Control-group; n = 4). Our findings demonstrated that serum values of BHBA, NEFA, insulin and cholesterol were significantly higher in cows with SCK comparatively with those of controls. Indices of insulin sensitivity showed a significant decrease in RQUICKI and a significant increase in HOMA in cows with SCK compared with controls. In comparison with controls, cows with SCK showed a significant increase in serum SODCows received RPC showed statistically significant lower values of BHBA than other supplemented groups. Only cows received RPN and RPC were greatly affected by the time and showed significant alterations in values of BHBA and NEFA (in both groups) and glucose and insulin in RPN-treated group. NEFA, glucose and insulin showed a distinct decrease in cows received RPN compared with those in other supplemented groups; their levels did not reach the statistical significance.