This study aims to investigate the chemical and immunological properties of powdered egg yolk antibody (IgY) on passive immunity and its possibility of absorbtion for dairy calves. A total of eighty white Leghorn hens was immunized by vaccine derived from E.Coli O78:K80 (as a contributing factor in the incidence of diarrhea in calves) at 42 week of age. Blood and egg yolk samples were collected weekly and the protein levels (in serum and yolk) were measured by Bradford method. Eggs were collected during the experiment and yolk antibodies were extracted by organic solvents chloroform, phosphate-buffered saline and PEG 6000 polymer, and finally dried by freeze drying method. Before the field study, the required amount of colostrum from first milking fresh cows collected in 4 liter containers. Ten newborn Holstein calves (5 heads per treatments) were assigned to 2 treatments including feeding colostrum with and without 40 grams IgY powder mixture. Then, 2 liters of the-second-serving pooled colostrum were fed to all calves, similarly. Blood samples were collected to estimate the absorption efficiency of IgY at birth time, 24 and 48 hours after the birth. Following oral administration of IgY powder to the newborn calves, the transfer efficiency of 17% IgY was obtained, which led to the presence of 1.37 and 0.833 milligrams IgY per milliliter blood in both 24 and 48 hour of live calves. Keywords: Egg Yolk Antibodies, Escherichia coli O78: K80, Antibody Blood Absorption, Purification
