Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2006
Publication Date: 9/1/2006
Citation: Godden, S., Mcmartin, S., Feirtag, J., Stabel, J.R., Bey, R., Goyal, S., Metzger, L., Fetrow, J., Wells, S., Chester-Jones, H. 2006. Heat-Treatment of Bovine Colostrum. II: Effects of Heating Duration on Pathogen Viability and Immunoglobulin G. Journal of Dairy Science. 89(9):3476-3483. Interpretive Summary: Morbidity and mortality in neonatal calves is a major concern for dairy producers. Evidence suggests that calves can become infected shortly after birth by exposure to pathogens such as Mycobacterium paratuberculosis, Salmonella, and Mycoplasma in either the feces or milk of infected dams, bedding or cohabitation with other infected animals. These pathogens may be spread to calves through colostrum from sick or infected cows. Some producers have opted to feed colostrums replacers to their calves to avoid the potential spread of disease. However, this is an additional expense that some producers cannot afford. Pasteurization of colostrum is an economical alternative to commercial colostrums products, however, little is known about its effectiveness in destroying pathogens or on the immunoglobulin content. This study demonstrated that a commercial pasteurization unit designed for on-farm use could be used successfully without destroying the immunoglobulin content. This information provides a useful management tool for dairy producers in allaying the spread of infectious disease to their calves and improving their health.
Technical Abstract: Batches (30-L) of first-milking bovine colostrums, inoculated with Mycoplasma bovis (10^8 cfu/ml), Listeria monocytogenes (10^6 cfu/ml), Escherichia coli O0157:H7 (10^6 cfu/ml), Salmonella enteritidis (10^6 cfu/ml), and Mycobacterium avium subsp. paratuberculosis (Map; 10^3 cfu/ml), were heat-treated at 60°C for 120 min in a commercial on-farm batch pasteurizer system. Duplicate 50-ml subsamples of colostrums were collected at 15-min intervals throughout the heat-treatment process for the purpose of bacterial culture and for the measurement of IgG concentration (mg/ml) and antibody activity (log2(bovine viral diarrhea virus type 1 serum neutralization titer)). Four replicate batches of colostrums were run for each of the 5 pathogens studied. There was no effect of heating moderate- to high-quality colostrums at 60°C for at least 120 min on mean IgG concentration (pre = 60.5 mg/ml; post = 59.1 mg/ml). Similarly, there was no effect of heat-treatment on the mean log2 bovine viral diarrhea virus type 1 serum neutralization titer (pre = 12.3; post = 12.0). Viable M. bovis, L. monocytogenes, E. coli O157:H7, and S. enteriditis added to colostrums could not be detected after the colostrums was heat-treated at 60°C for 30 min. Average bacteria counts showed that Map was not detected when batches were heated at 60°C for 60 min. Although the authors believe that heat-treating colostrums at 60°C for 60 min should be sufficient time to eliminate Map from colostrums in most situations, further research is needed to determine whether these findings may be replicated, given that variability was observed in Map culture results.