BSTP Testing Using CR
(Blood serum total protein testing when feeding colostrum-derived colostrum replacer)
The question came up about what standards to use when checking for passive immunity when colostrum-derived colostrum replacer is being fed to newborn calves.
Calves are being fed within an hour or two after birth. They receive between 180 and 200g of IgG in one feeding. Blood is drawn on day two for blood serum total protein testing. When feeding maternal colostrum the dairy was using the goals of 90 percent of calves at or above 5.0 and 75 percent of calves at or above 5.5g/dl.
Is it appropriate to use the same standards now the calves are being fed colostrum replacer?
Fortunately, this question has been investigated (J. Helz, S. Godden, D.M. Haines, K. Leslie, "Association between serum total protein and immunoglobulin G measures in calves fed a whole colostrum derived colostrum replacer" AABP Proceedings, September, 2009, p195.).
The research included 187 calves from three different studies. They measured IgG directly as well as obtaining blood serum total protein values. The value of 10mg/ml is used as the minimum standard for successful passive transfer. Both maternal colostrum (one half of the calves) and maternal-derived colostrum replacer had blood serum total protein values of 5.0g/dl when the IgG value was 10mg/ml.
The authors concluded, "Producers can use the same serum TP cutpoint of 5.0g/dl to estimate passive transfer (IgG of 10mg/ml) whether the calves are fed whole colostrum derived colostrum replacer or maternal colostrum."
The authors note that they did not investigate this relationship for plasma-derived colostrum replacer.