The nutritional effects of supplementing the diets of dairy cows during the dry period with anionic salts and probiotic, on some blood parameters. milk production and composition and the development of milk fever, were evaluated in 20 Holstein cattle (>3(rd) lactation), Diets were composed of a mixture of hay (70%) and commercial concentrate (30%) with and without Supplemental anionic salts. These diets were given to cows during the 3 weeks prior to calving. Cows in the probiotic group also received 5g/day probiotic orally during this period. The cation/anion balances of the diets were determined to be -67.77 and +130.73 meq/kg dry matter in the anionic diets and the control diets, respectively. Blood Samples were collected 21, 14 and 7 days prior to calving. at calving and days 1, 2, 7, 14. 21 and 42 postpartum. Milk samples were collected on days 7, 14, 21 and 42 postpartum, Urine samples were collected 3 weeks prior to calving. at calving and at the sixth week postpartum. Dry matter intake amongst the groups was not affected by trials. Serum Ca levels of cows consuming the control diet were found to be significantly lower than those of the other groups on the first day postpartum (p<0.05). On the day of calving, serum Mg levels of all animals in all groups were found to be increased and serum Ca (except the anionic group) and P-1 levels were decreased. However, serum total protein and albumin levels were not affected during this experiment. The urine pH level of the control group was highest at the parturition (p<0.05). Milk production in the anionic salt and probiotic groups was increased during the 2(nd) week of lactation compared with the other groups (p<0.05). Milk composition was not affected significantly during the trial. Milk fever developed in one animal in the anionic salt + probiotic group, and in two animals in the control group.