Total complement hemolytic activity of colostral whey and sera from dairy cows.

Two methods were used to clarify bovine colostrum for quantitation of total complement (C') hemolytic activity in the whey. The renin precipitation method produced whey which tended to have higher C' hemolytic activity (5.0 +/- 3.4 CH50 units) than did whey prepared by ultracentrifugation (2.5 +/- 2.6 CH50 units) although this difference was not significant. No correlation was found between levels of complement in the sera of cows at parturition and in the colostral whey from the same animal. Total complement activity was not detected in milk taken a 96 hours or one month after parturition. This is apparently the first report of quantitation of total C' hemolytic activity in bovine colostrum.