Abstract: The incidence of brucellosis among examined cows by different diagnostic tests on milk and whey were 11 (22.91%), 10 (20.83%), 8 (16.66%), 7 (14.58%) and 11 (22.91%) for Milk Ring Test (MRT), Whey Rose Bengal Plate Test (WRBPT), Whey Microtiter Agglutination Test (WMAT), Whey Dithiothereitol Agglutination Test (WDAT) and Delayed type Hypersensitivity Test (DHT) respectively. The results of absolute specificity were 26.31, 20.0, 17.07, 29.72 and 29.72% with WRBPT, WMAT, WDAT, MRT and DHT, respectively. The highest incidence of DHT (22.91%) indicated that the sensitivity of this test, which depends upon the cellular immunity response, was independent from specific humoral antibody production. The concordance between reactors cows in the different tests used in this study were 100.0, 97.51, 93.75 and 91.66% for MRT, WRBPT, WMAT and WDAT, respectively. It is noticed that the DHT achieved the highest agreement with MRT (100%). Only one isolate of Brucella melitensis biovar 3 could be isolated from milk samples which gave positive with MRT. The results evident that the whey of cows included closed bands in case of infected samples if compared with free and healthy one. Within -Lg three genotypes were observed: AA, AC and CC. Homozygote CC had the greatest number (5) of these genotypes, but, heterozygote AC had the lowest number (1). A higher frequency for allele C of -Lg than allele A of -Lg gene was observed (0.687 and 0.312), respectively. Within -La the presence of three genotypes were appeared: AA, AB and BB, the highest number being recorded for homozygote BB with higher frequency in -La^B gene (0.812) than in all fractions of whey proteins. Concerning the -globulin (S ₂), the same genotypes of -La were observed for this fraction, with higher frequency in S ₂^B than S ₂^A (0.687 and 0.312), respectively. The observed homozygous genotype in -Lg, -La and -globulin variants of whey proteins were higher than those expected heterozygous genotypes. Results revealed that the infected cows suffering from brucella distinguished by high frequency of homozygotic genotypes in all studied loci with predominance of -La^B gene marker.