Colostral immunoglobulin concentrations were compared among five breeds of dairy cows. Colostrum samples (3 to 4 kg) were obtained immediately after parturition from 19 Ayrshire, 17 Brown Swiss, 12 Guernsey, 19 Holstein, and 5 Jersey cows. Average total colostral immunoglobulin was 8.1, 6.6, 6.3, 5.6, and 9.0% for them. Colostrum from Jerseys had the highest immunoglobulin G (6.65%), immunoglobulin A (1.86%), and immunoglobulin M (.53%) of all breeds. Colostrum from Holsteins was lowest in immunoglobulin G (4.12%) whereas that from Guernseys was lowest in immunoglobulin A (.90%) and immunoglobulin M (.39%). Breeds may differ, and the high calf mortality and health problems frequently reported for Guernseys may be related to the low immunoglobulins A and M in colostrum. Concentration of colostral immunoglobulin by calving number was examined over breeds for 23, 16, 17, and 14 cows by first, second, third, and fourth or later calvings. Colostral immunoglobulin was lower from first-calf heifers (5.68%) than from third (7.91%) and fourth (7.53%) parity cows. Colostral immunoglobulins A and G tended to be lower in first lactations.