Using a refractometer to test colostrum

Here at Refractometer Shop we don’t claim to know the meaning of life, but we do know that colostrum quality is key to giving livestock a meaningful start.

Foals, calves and lambs with low levels of immunoglobulin are in danger of becoming immunologically compromised and at times are in a potentially life threatening position at birth. Using a refractometer to monitor colostrum quality fed to newborns can help to ensure that offspring receive enough immunoglobulin, increasing the survival rate of new livestock.

A simple method to determine colostrum quality at birth is by refractometry.

Measurements can be taken using a Bellingham + Stanley Eclipse handheld refractometer, available from Refractometer Shop. By taking a well-mixed colostrum sample and placing a small drop onto the glass prism and referring to the conversion table below, you’ll be able to easily tell if the sample is poor, adequate or very good.

To take a reading using an optical refractometer you simply open the flap, apply a sample to the glass prism, close the flap and look through the eyepiece. The results will be shown by a shadowed line through the scale. We call this the borderline.

For an even quicker and easier method we recommend the use of an OPTi digital refractometer. Simply apply the sample to the prism dish & press “read”. No look-up tables or conversions necessary, the OPTi will do the work for you before telling you in English whether the sample is good to use or not.

The use of a refractometer allows the level of immunoglobulin to be assessed quickly (in seconds) and effectively and immediate treatment can follow. The refractometer is an invaluable and simple aid to securing these measurements without the need for large, valuable amounts of sample.

Colostrum quality conversion table

BRIX % IgG Conc. g/l Colostrum Quality
<10-15% 0-28 Poor
15-20% 28-50 Borderline
20-30% 50-80 Adequate
 >30% >80 Very Good


For more information about Eclipse and OPTi refractometer click here.

Colostrum quality refractometers