Antibodies not fed never end up in the blood
In a recently reported research project calves were fed maternal colostrum, plasma-derived colostrum replacer and colostrum-derived colostrum replacer.
One factor influencing the results (maybe depressing the effectiveness of colostrum replacers) was that the colostrum replacers were fed in enough water to make 4 quarts total volume regardless of the package directions to use less water. [plasma-derived colostrum replacer recommends using 1.5 quarts water, colostrum-derived colostrum replacer recommends using 1.3 quarts.]
The amounts of antibodies fed, respectively, were 190g, 150g and 100g.
One measure of antibody passive transfer is blood serum total protein levels. They were, in the order given above, 6.1, 5.3 and 5.3.
Another way to estimate antibody passive transfer is serum immnoglobulin type g levels (Serum Ig). These blood (serum Ig) levels were, respectively, 2,098mg/dL, 926mg/dL and 1,139mg/dL.
Another way to look at these results is the percentage of calves with blood serum total protein levels of 5.2 or greater. These percentages in the order given above were 92%, 29% and 49%.
Moral of the story: antibodies not fed never end up in the blood. If you are going to feed colostrum replacer plan on feeding a minimum of 200g of antibodies. This requires feeding more than one 150g or 100g package of colostrum replacer.
D. Priestley, JH Bittar, L Ibarbia, CA Risco and KN Galvao, "Effect of feeding maternal colostrum or plasma-derived or colostrum-derived replacer on passive transfer of immunity, health, and performance of preweaning heifer calves." Journal of Dairy Science 96:3247-3256. 2013.