A: By using a colostral refractometer

Colostrum milk is the first type of milk produced by mammals in the very late stages of pregnancy and immediately after giving birth. This has a high importance in the livestock industry as colostrum milk is a source of passive immunity for new born calves, foals and lambs due to its richness in immunoglobulins (namely IgG) ensuring they stay healthy in their early stages of life whilst their own immune system develops.
Using a refractometer you can measure the quality of colostral milk. Refractometers measure the refractive index of a liquid which is then converted to a measurement reading – usually % Brix (sugar). The colostral refractometers measure the % Brix and using this value the IgG concentration and thus colostrum quality can be determined.
BRIX % | IgG Concentration g/l | Colostrum Quality |
<10-15% | 0-28 | Poor |
15-20% | 28-50 | Borderline |
20-30% | 50-80 | Adequate |
>30% | >80 | Very Good |
We have the following refractometers available:
Digital Refractometer Range (OPTi):

This pocket-sized stainless steel refractometer has an easy to read LCD screen with a silicone rubber keypad.
Key features include:
- IP65 rating.
- Automatic temperature compensation.
- Range : 0-35% Brix/ colostrum quality
- Accuracy : +/- 0.2% Brix / poor or PASS
- Resolution : 0.1% Brix / poor or PASS
- Results can be displayed automatically as poor or pass without the need of manually converting the % Brix reading to the associated IgG concentration values.
- Requires calibration but has the option to facilitate the use of long life AG calibration fluids without the need to consider measuring ranges. All models of the OPTi refractometers also feature a water (zero) calibration mode.
- Available to purchase here.

This classic optical refractometer features a metal design with a rubber handgrip with polyurethane illuminator flap. Supplied in a soft carry case.
Key features include:
- IP65 rating.
- Clear and easy to read scale.
- Reading in the % Brix scale range 0-30 with division of 0.2.
- Supplied with a conversion table to allow you to manually convert the reading to determine colostrum quality.
- Available to purchase here.
Both of the above mentioned refractometers are supplied with a certificate of calibration in the box, traceable to NIST and ICUMSA standards. They are factory calibrated using UKAS certified reference material.
We stock a range of refractometers covering many scales designed for numerous applications. If you require any further information about this application or refractometers in general, do not hesitate to contact us at support@camlab.co.uk or using the below contact form.