Purpose: This study aimed to reduce MAP in colostrum using curdling (for on-farm treatment) and centrifugation (for off-farm treatment at a central location).
Methods: Different conditions for curdling and centrifugation were evaluated, such as rennet type and concentration; centrifugation speed and time; and diluting colostrum and skimming before treatment. The total protein and immunoglobulin concentration were determined by the Coomassie Bradford assay and gel filtration, respectively. An animal experiment was conducted (24 calves; 4 groups; health parameters, IgG blood value, and consumability).
Results: The on-farm protocol included diluting the colostrum with water (2/1), curdling with 2% calf rennet, separation of whey and curdle, and adding milk powder to the whey before administration to the calf. With this protocol, one log MAP reduction/ml colostrum was observed. The off-farm protocol included diluting the colostrum in a two to one ratio with skimmed colostrum and subsequent skimming and clarifying. On average more than 1.5 log reduction in MAP presence and a limited reduction in proteins and IgGs was seen. We found no significant differences between test and control groups, during the animal experiment.
Significance: We developed two protocols for MAP reduction in colostrum, which could lead to a reduction of MAP presence in cows, and could be, successfully, used in the Belgian MAP reduction program on dairy farms. This program is an important measure for reducing the risk of MAP intake by consumers.