Location: Infectious Bacterial Diseases ResearchTitle: Heat treatment of colostrum on commercial dairy farms decreases colostrum microbial counts while maintaining colostrum immunoglobulin G concentrations Author
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2012
Publication Date: 5/7/2012
Citation: Donahue, M., Godden, S., Bey, R., Wells, S., Oakes, J., Sreevatsan, S., Stabel, J.R., Fetrow, J. 2012. Heat treatment of colostrum on commercial dairy farms decreases colostrum microbial counts while maintaining colostrum immunoglobulin G concentrations. Journal of Dairy Science. 95(5):2697-2702. 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 avium subsp. 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 pasteurization decreased bacterial counts in the colostrum 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: This study was conducted on six commercial dairy farms in Minnesota and Wisconsin to describe the effect of heat-treatment of colostrum, at 60o58 C for 60 minutes, on colostrum bacteria counts and immunoglobulin G concentrations. First milking colostrum was collected each day, pooled, divided into two aliquots, and then one aliquot was heat-treated in a commercial batch pasteurizer at 60.C for 60 minutes. Frozen samples of pre- and post- heat-treated colostrum were submitted for standard microbial culture (total plate count, total coliform count, (cfu/ml) and testing for immunoglobulin G concentrations (mg/ml). Data were analyzed from 266 unique batches of colostrum. Linear regression showed that heat-treatment reduced colostrum total plate counts (-2.25 log10) and coliform counts (- 2.49 log10), but, overall, did not affect colostrum IgG concentration. Though higher quality batches of colostrum did experience a greater magnitude of loss of IgG as a result of heat-treatment as compared to lower or intermediate quality batches of colostrum, the colostral IgG concentrations in these batches remained high overall, and within acceptable limits for feeding. This study demonstrates that batch heat-treatment of colostrum at 60.C for 60 minutes can be successfully conducted on commercial dairy farms by farm staff to reduce colostrum microbial counts while maintaining colostrum IgG concentrations.