Colostrum management is the single most important step in calf rearing. It determines immunity, early-life health, growth rates and long-term performance. Many issues such as scour, pneumonia and poor thrive start with inconsistent feeding practices, poor hygiene or incorrect temperatures in the first hours after birth.

This guide brings together core principles of good colostrum feeding and all key insights from the on-farm video, including the correct use of bottles, bags and tubes, how to manage colostrum equipment, understanding feeding systems and keeping temperature consistent.

 

What Is Colostrum?

Colostrum is the first milk produced immediately after calving. It contains extremely high levels of immunoglobulins, antibodies, nutrients, vitamins and energy. Unlike whole milk, colostrum is thicker, richer and specifically designed to transfer immunity to the newborn calf, which is born without natural protection.

 

Why Colostrum Feeding Matters

Because calves are born with no immunity, the antibodies present in colostrum are essential for fighting disease during the first weeks of life. Correct colostrum feeding reduces scour and pneumonia, improves vigour, supports early growth and lowers treatment requirements. Poor colostrum management is one of the most common root causes of early calf illness.

 

How Much and When to Feed Colostrum

A newborn calf should receive three to four litres of good-quality colostrum within the first two hours after birth, followed by a second feed of around two litres eight to twelve hours later. Early feeding is critical, as the calf’s ability to absorb immunoglobulins declines rapidly from birth and becomes very limited after twelve hours.

 

Assessing Colostrum Quality

The most reliable way to assess colostrum is with a Brix refractometer. A reading of 22% or higher indicates good-quality colostrum. Factors such as leaking before calving, short dry periods, inadequate dry cow minerals or high milk yield at calving can reduce antibody concentration. 

How to Tell If the Calf Received Enough

Blood testing calves at 24–48 hours (serum total protein) provides a clear indication of passive transfer, with values above 5.5 g/dL showing good absorption. Calves that are bright, vigorous, well hydrated and quick to drink generally indicate successful colostrum management.

 

Bottle, Bag or Tube — Why the Method Does Not Affect Immunity

Latest research shows very little difference in absorption efficiency between feeding with a bottle, bucket, colostrum bag or stomach tube. The feeding method itself is not the determinant of success. Clean equipment, correct temperature, rapid feeding and consistent practice matter far more. The goal is always the same: deliver clean, high-quality colostrum quickly and with as little stress as possible.

 

When Tubing Is the Right Choice

Tubing is appropriate when a calf has low vigour, no suck reflex, or lacks the strength to drink. Some calves may also require tubing for the second feed depending on their progress. If a calf continues to refuse to drink, farmers should consider whether a health issue is present, whether the calf simply needs more time, or whether further tubing is suitable. There is no fixed rule for when to stop tubing; these decisions should be made case by case, always prioritising the calf’s condition and safety.

 

Different Colostrum Feeding Systems

Irish farms use a range of colostrum-feeding systems. Some provide one or two colostrum feeds and then move straight to milk replacer. Others feed transition milk for several feeds to extend colostrum’s natural benefits. Evidence from extending transition milk feeding well beyond the first colostrum feed—ranging from 9–10 feeds, to 10 days and even 3 weeks showed benefits spanning short-term health and growth to longer-term lactation performance.

 

Managing Colostrum Bags and Tubing Properly

Colostrum bags and tubing require careful cleaning and maintenance. They must be washed thoroughly after every use, as colostrum’s high fat content allows bacteria to grow quickly if not removed. Bags or tubes showing cracks, fraying, hardened plastic or any sign of perishing should be discarded immediately, as damaged equipment is extremely difficult to clean.

Every farm should keep separate feeders: one for healthy calves, another for sick calves and a third used exclusively for electrolyte administration. Sharing the same bag or tube for both electrolytes and colostrum significantly increases the risk of cross-contamination and disease spread, including rotavirus and E. coli.

 

Cleaning Colostrum Equipment Correctly

Cold water rinsing is ineffective because colostrum is fatty. Cleaning must begin with warm water, followed by a proper detergent wash, brushing inside narrow sections of the tube and finishing with a disinfectant rinse. A thin bottle brush is essential for reaching inside the tubing, where residue often accumulates. Equipment must then be dried fully and stored in a clean, dry area to prevent bacterial growth.

 

When Electrolytes Should Be Tubed

Tube-feeding electrolytes is appropriate only for very sick calves, such as those with severe rotavirus scour or those unable to stand and drink. This must be carried out using a separate dedicated tube feeder to avoid contaminating colostrum equipment.

 

Feeding Temperature — One of the Most Overlooked Factors

The ideal feeding temperature for colostrum, whole milk or milk replacer is 41–42°C, slightly above calf body temperature. Milk that falls below this causes calves to drink slowly, struggle to digest efficiently and use additional energy to warm it internally, which reduces growth. Milk that is too hot risks damaging proteins, especially in thick colostrum.

One of the biggest practical issues on farms is temperature drop. The first calf often receives milk at the perfect temperature, while the last calf receives milk considerably cooler. This inconsistency affects digestion and energy use and increases digestive upset.

Tools such as thermometers, milk heaters or warm-water mixing systems help maintain a consistent temperature across all calves, not just the first.

 

Can Colostrum Replacers Be Used?

Colostrum replacers have a place on farm, especially when natural colostrum quality is low, a cow has no colostrum or disease control protocols advise against pooling. While replacers do not match the full immune profile of maternal colostrum, they are a valuable alternative when needed.

 

How to Store Colostrum

Colostrum can be refrigerated for short-term use and should be used within 24–48 hours. For longer storage, freezing in one or two-litre bags is ideal. Bags should be clearly labelled and thawed gently in warm water at 40–45°C. Avoid overheating, as excessive temperature destroys antibodies.

 

Conclusion: Consistency, Cleanliness and Correct Execution

The science is clear: colostrum feeding succeeds when farmers deliver good-quality colostrum, in the right quantity, at the right time, with excellent hygiene and consistent temperature control. Whether a bottle, bag or tube is used matters far less than how well the process is carried out. Good equipment management, safe tubing decisions and well-stored colostrum all play a central role in building strong immunity and supporting healthy growth throughout the calf’s early life.

For tailored calf-rearing advice, support with early-life nutrition or guidance on feeding systems for your farm, contact the Specialist Nutrition team.