Why colostrum quality matters

Ensuring calves get the best possible start in life is essential for building a healthy, productive herd. One of the most important factors in early calf health is the quality of colostrum — the first milk produced by a cow after calving.

Colostrum is rich in nutrients and antibodies that are critical for a calf’s immune system and development. However, not all colostrum is the same, which makes testing its quality an important step before feeding it to newborn calves.

What is colostrum?

Colostrum is the first milk produced by a cow after calving and contains high levels of immunoglobulin G (IgG) antibodies. These antibodies are essential for transferring immunity from the cow to the calf, helping protect against disease in the early stages of life.

The quality of colostrum can vary depending on factors such as nutrition, breed, age, and how soon it is collected after calving. In general, colostrum from mature cows tends to be higher in quality than that from first-time calvers.

As a guideline, good quality colostrum should contain at least 50 grams of IgG per litre to provide adequate protection.

The 1-2-3 rule of colostrum feeding

A simple way to help ensure calves receive sufficient colostrum is to follow the 1-2-3 rule:

• Use the first milk
• Feed within two hours of birth
• Provide at least three litres of good quality colostrum

Colostrum may continue to be fed for up to 24 hours after birth, as the calf’s gut can still absorb immune-related proteins during this period. After passive immunity is established, calves can transition onto milk or milk replacer.

What makes good quality colostrum?

To maximise its effectiveness, colostrum should:

• Be free from bacterial contamination, as this can interfere with IgG absorption
• Be fresh, as it can spoil quickly and lose nutritional value
• Be fed as early as possible, ideally within the first few hours of life

The risks of poor quality colostrum

Feeding low-quality colostrum can increase the risk of health issues such as scours and respiratory disease. In more severe cases, it can lead to higher mortality rates.

Calves that do not receive enough antibodies early in life are also more likely to experience reduced growth and long-term performance issues, impacting overall herd productivity.

Testing colostrum quality

Testing colostrum before feeding is a simple and effective way to ensure calves receive the protection they need. One of the most practical tools for this is a Brix refractometer.

A Brix refractometer is a handheld device that measures the sugar content of a liquid, which can be used to estimate colostrum quality.

How to test colostrum using a Brix refractometer

• Ensure the sample is at room temperature, around 20–25°C
• Mix the colostrum well to create a consistent sample
• Place a few drops onto the prism
• Close the cover and look through the eyepiece to read the result

Interpreting Brix readings

• Less than 22% → Poor quality
• 22–24% → Good quality
• Greater than 24% → Excellent quality

Brix readings provide a useful estimate, but should be used alongside good management practices to ensure the best results.

Building a strong foundation for calf health

Prioritising colostrum quality is one of the most effective steps you can take to improve calf health and long-term herd performance. A consistent approach to testing, feeding, and record keeping helps reduce risk and ensures every calf gets the best possible start.

Using Herdwatch to stay on top of calf health

Managing colostrum feeding and early-life treatments can be challenging, particularly when multiple calves are involved. Herdwatch helps simplify the process by allowing you to:

Record colostrum feeding in real time

Log key calf health actions as they happen, helping improve accuracy and reduce missed details.

Track calf health from day one

Keep a clear record of treatments, progress, and early-life management decisions for every animal.

Keep records organised and accessible

Maintain accurate records for compliance, team communication, and better day-to-day decision-making.

Support more consistent calf management

With everything in one place, Herdwatch helps you stay organised and maintain a consistent approach across your calf-rearing process.