The study evaluated the effect of incorporating dried distillers' grains with solubles (DDGS) into the cow's diet during the dry period on colostrum quality, concentrations of protein, and immunoglobulin G (IgG) in the serum of cows and calves. Three weeks prior to the expected calving date, cows were selected and assigned to four groups, each comprising 15 animals. The standard group (Group I) was fed a standard total mixed ration (TMR). Groups II, III, and IV received TMR supplemented with DDGS at rates of 1 kg, 2 kg, and 3 kg per head per day, respectively. Colostrum and blood samples were collected from all cows. Blood samples were also obtained from calves on the 3rd and 30th days of life. Analyses of colostrum: basic composition, amino acid profile, IgG, IgA, IgM, protein fraction distribution, and concentrations of Ca, P, Mg, K, and Na. In blood samples, total protein content and IgG levels were determined. Colostrum from cows in groups I and IV had decreased lactoferrin level compared to group II. In group III, an increase in IgG and total protein levels was observed. Regardless of the DDGS supplementation levels in maternal feed rations, an increase in total protein and IgG levels was noted in the serum of calves on both the 3rd and 30th days of age. These findings suggest that the use of DDGS in cow's diets during the pre-calving period appears to enhance colostrum quality, and would seem to increase immunoglobulin levels and improve passive immunity in calves.