Assessment of immune quality and pathogen contamination of colostrums collected from colostrum banks in Korea

Because colostrum is considered to be the sole source of passively acquired maternal antibodies for calves, newborn calves must consume colostrum to gain disease resistance during their early years of life. Storage of surplus colostrum from dairy cows right after calving and feeding newborn calves in deficiency of colostrum to assure adequate uptake of IgG for protection of the calf has been a common practice in the bovine production. In the current study, 35 colostrums were randomly collected from 3 colostrum banks located in different regions of Korea and monitored for general bacterial contamination and major bovine pathogens. Immunoglobulin concentrations and BVDV-specific antibodies were also determined to evaluate the immune quality of the colostrums. Moderate to severe bacterial contamination (up to 72,000,000 CFU/ml) was observed in most of the colostrums collected from colostrum banks. General immune quality of the colostrums was under the satisfactory level since most of the colostrums contained less than 50 g/L of IgG, which is the minimum concentration for good quality colostrums. Therefore, colostrum for colostrum bank should be collected at the first 2-3 post-partum milkings according to proper harvesting and handling procedures to guarantee the safety and quality of colostrum. In addition, it was recommended that colostrum should be heat-treated before frozen and stored in the bank because pasteurization at 63°C for 30 min was very effective reducing the risk of disease transmission without causing significant degradation of immunoglobulins.