This was a case of many too many cases of passive transfer failure. The farm was facing a management challenge due to Johne's disease. One of the control measures adopted was to feed a colostrum replacer rather than maternal colostrum to newborn calves. The bag indicates the product should be mixed with 5 cups of 110-120F water and that feeding 2 bags is recommended for good passive transfer of immunity.

Following an extended episode of scouring calves the herdsman was convinced to check immunity levels among baby calves. The results revealed that too many of the calves had blood serum total protein levels below 5.0 - a commonly accepted threshold to determine passive transfer failure.

A review of mixing procedures showed that the water being used was both the correct temperature and volume. Since time of birth and time of colostrum replacer feeding were recorded for each calf it was easy to confirm that feedings were being done promptly after birth.

As we talked a worker came into the utility room to mix colostrum replacer for a newborn calf. She ran water in a pail, opened two packages of the colostrum replacer and proceeded to mix.

You need to know that the dairy initially used a colostrum replacer with 100g IgG per package and fed 2 packages to each calf. Somewhere along the line the decision was made to switch to a colostrum replacer packaged with 60g IgG per package. Have you already guessed what happened.

Yes, you are correct. The new product's mixing instructions used the same temperature water but a different volume. That part got through to the folks mixing the product. However, the new product says, "To replace maternal colostrum feed calf 3 bags."  Ooops! Somehow that part of the directions was overlooked. Instead of feeding the recommended 180g IgG the calves were only receiving 120g.

The story does have a good ending. Once the protocol was corrected to use 3 bags of product per calf the blood serum total protein values improved and the proportion of calves needing treatment for scours went down. Amazing, reading ALL the directions does improve performance of a product.