A simple way to measure the antibody level of colostrum. Simple red-amber-green system. An example of how it is used in the USA:-
Nipple color indicates type of colostrum
By Dairy Herd staff | 5/1/2007
At Galeton dairy, Galeton, Xolo., all calves receive colostrum — even bulls.
All colostrum is tested with a colostrometer. If it scores green, it is pasteurized and then stored in the refrigerator in bottles ready to feed. Cow colostrum, which is reserved for heifer calves, is stored in bottles with a red nipple. Colostrum from first-calf-heifers is fed to bulls and stored in bottles with a black nipple. This way, employees know at a glance which bottle of colostrum to feed to a newborn. And if they have more than one newborn to feed, the bottles don’t get mixed up on the way to the newborn area.
More information at http://www.colostrometer.com/
and use of colostrometer at http://www.calfnotes.com/pdffiles/CN022.pdf