News & Advice

Timing of colostrum is vital

Jul 7, 2021 | Dairy, Grazing youngstock, Young Stock

Arnica van der Wiele, Veterinarian, Anexa Vets Ngatea

The calf

Did you know that my gut can only absorb antibodies from colostrum into my blood in the first 24 hours of my life. From the moment I am born the temporary “openings” in my gut that allow me to absorb the large antibodies start closing, so the sooner I get colostrum, the more I can absorb. After 24 hours, the ‘gates’ close. Colostrum from then on is still an excellent feed, coating the intestines with antibodies, but these will not enter the bloodstream.



Did you know that the antibody levels in my colostrum will drop rapidly, regardless of whether you have milked me or not. At time of calving antibody levels are at peak, after 12 hours they have about halved in concentration and after 24 hours they have halved again. This compromises the future health of my calf.


Colostrum collection drum/bucket

Did you know that from the time of collection, antibody levels in colostrum start dropping? Not only do antibodies in the colostrum break down with time, bacterial contamination of the colostrum means the gut cannot absorb as many antibodies.

Antibodies need to be absorbed into the bloodstream in order for the immune system to be able to respond to a challenge (virus/bacteria/other pathogen (disease causing organism). If no antibodies have been absorbed, a calf is at mercy of any disease entering the system and will be more likely to become severely ill.

This is why timing of colostrum is so vital!


What can you do to give your replacements the best start:

Measure the pooled first milking (“gold”) colostrum with a Brix refractometer: You want a reading of 22% or more. If you measure the pool of colostrum for newborn calves and it reads under 22% on the Brix refractometer then take the following steps:

  1. Check that the colostrum you are adding to the pool for newborn calves is fresh first-milking colostrum (not mixed with days two, three and four colostrum/transition milk).
  2. Try to minimise the time between calving and when the colostrum is first collected from fresh cows; the antibody level declines really quickly the more time that passes.
  3. Look at individual cow risk factors for poor quality colostrum; consider testing individual cow colostrum with the Brix refractometer to make sure only the best cows are selected to contribute to the pool. Good practice is to have two collecting vats for colostrum: one for colostrum with Brix >22% and one for colostrum with Brix <22%. The good stuff (>22%) goes to newborns and the other colostrum can be fed to older calves.
  4. Minimise the time between collection of first milking “gold” colostrum and feeding that colostrum to newborn calves as the antibody concentration declines in the bucket as well as in the cows udder (prior to collection).
  5. Even if the antibody level is good, bacteria in the colostrum are a problem. Bacteria in colostrum cause souring and spoilage. Bacteria can also block the absorption of antibodies even if there are enough antibodies in the colostrum.
  6. If you have Brix <22% and you are using it for the first feed for newborn calves consider increasing the volume i.e. instead of 2L feed 3L. In small calves you will need to split this into 2 1.5L feeds 4 h apart.

Samples collected from all over New Zealand showed that bacteria levels are very high in pooled colostrum for newborn calves. Bacteria typically come from four sources: the cow; the test bucket; the storage vat; and the feeders. 

Cleaning all your feeding and storage equipment, as well as minimising contamination from the cow herself is the key to keeping colostrum clean and suitable for feeding to calves. Use hot water and detergent to rinse off the fatty residues left by colostrum and rinse off the detergent fully before using your equipment. 

Once you are happy that your colostrum is the best possible quality you can achieve, consider preserving it. A safe and reliable option for colostrum preservation is potassium sorbate. Instructions on how to use this can be found in each Anexa clinic.

Talk to us if you want us to set you up with a fail-proof system for your colostrum management.


Anexa info sheets you may find helpful:

Colostrum management.pdf

How to use a brix refractometer to measure colostrum quality.pdf

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