All Colostrum is Not the Same
Recently published work (A. Soufieri and Others, "Genetic parameters of colostrum traits in Holstein dairy cows." Journal of Dairy Science, 102:11225-11232, 2019) collected colostrum samples from 1,047 healthy Holstein dairy cows.
The yield was recorded as well as Brix values obtained from each cow's first milking. Laboratory analysis determined both fat and protein content.
Yield The median yield was 5kg (about 6.3 quarts). The lowest yield was less than 1 quart while the highest yield was nearly 11 quarts (23.5kg).
Brix values The median Brix was 25.9. The lowest Brix was 10.7 and the highest Brix was 41.4.
Fat percentage The median fat was 6%. The lowest fat was less than 0.1% while the highest fat percentage was 18.2%.
Protein percentage The median protein was 17.9%. The lowest protein was 4.8% while the highest protein percentage was 30.4%.
Conclusion? All colostrum is not the same. Keep using your Brix refractometer to sort colostrum before using for first feeding.