Checking the serum total protein of calves is a valuable tool for monitoring a farm’s colostrum program. Just make sure you test a representative sample of calves.

“It is best to check 10 calves before drawing conclusions about the farm’s colostrum program,” says Stan Moore with Michigan State University Extension. “Individual animals can sometimes be abnormal for a variety of reasons.”

Also be wary of very high readings on your refractometer. Certain conditions, like dehydration, may cause the test to show a high protein concentration “and a false assurance of successful passive transfer,” Moore says.