News & Advice

Colostrum & calf immunity – are we really doing as well as we think we are?

Jun 7, 2023 | Calf rearing, Dairy, Young Stock

Arnica van der Wiele, Veterinarian, Anexa Vets Ngatea

It would be nice to assume that we are doing a great job when it comes to colostrum management and calf rearing, and it is easy to think so if everything seems to be going well. However, when we dig a little deeper, we often find that things may not be quite as good as they seem. The following case study shows how a little investigation can lead to big improvements. If you think your calf rearing systems might benefit from a ‘systems check’, get in touch with your local Anexa vet today to plan the best approach.

Case Study: During spring calving in 2022 we tested antibody levels in blood samples from multiple groups of newborn calves (ranging from 24 hrs-7 days old) across several different farms, to measure if they had absorbed enough antibodies from colostrum. These farms weren’t experiencing disease outbreaks; they simply wanted to check if their colostrum management was working the way it should.

The initial results did not make for great reading:

  • None of the farms tested achieved 100% of calves with high enough antibody levels.
  • Results ranged from 15 to 100% of calves NOT having adequate levels.

We discussed the results of the first round of testing with the farmers and their calf rearers and made plans to carry out another round of blood tests on a new batch of calves on each farm three weeks later. The calf rearing and colostrum management systems were different on each farm, so the changes made were specific to each set-up. One positive change that we noticed across several farms was improved communication between the farm managers, the milkers collecting the colostrum, and the calf rearers feeding the calves.

In the second round of testing, three weeks later, most of the farms reached 100%, meaning virtually all the newborns tested had received sufficient quantities of good-quality colostrum. Interestingly the farm that had the poorest result in the first round of testing, thought they were doing a good job and were horrified to find that levels were inadequate. In the second round of testing, they achieved 100% – a great result!

This case study really demonstrates that you just don’t know if you are doing a good job until you measure it.


Failure of Passive Transfer

Failure to receive sufficient antibodies from colostrum, also known as ‘failure of passive transfer of immunity’ (FPT) is impossible to diagnose without testing. You can’t tell by looking at a calf if she has good immunity. The signs of poor immunity are often indirect and delayed: disease outbreaks, poor growth, not doing well, and sudden death can occur weeks or months later. Effects of failure of passive transfer of antibodies carry on way past weaning and will affect weight gain, general health, and future productivity.

In many areas of farming getting something “100% right” is often not a realistic target, but in the case of calf immunity, it is achievable because you can measure and control most steps in the process.


What can YOU measure?

On farm you can test the “gold” colostrum that you feed to calves. Colostrum for newborns should be collected from the first milking only after calving. Good quality colostrum has a BRIX reading >22%. A BRIX refractometer is a tool that measures colostrum quality using a single drop of colostrum. Refractometers are available from Anexa for $70.  Easy-to-follow instructions can be downloaded from the Anexa website, or you can ask your vet to show you – the process is very simple.


What can WE measure for you?

If you want to know if what you are doing is working, we can blood sample some calves in the right age bracket and measure the antibody levels in their blood. If we identify failure of passive transfer, we can then look at the process on farm and see what we can tweak to get you and your future dairy cows to the 100% mark.


Colostrum vaccines

Calf diarrhoea is a complex, costly, and devastating disease and providing your calves with specific antibodies against the big players in this field is an important part of the prevention of outbreaks. If given at the right time colostrum vaccines to prevent rotavirus and E.coli scours will not only provide your calves with specific antibodies against those diseases, but have also been shown to boost the overall concentration of IgG antibodies in colostrum.

Remember though that scour vaccines are only effective when colostrum management is up to scratch; the calves must drink enough, good quality colostrum soon enough after birth to maximise the benefit of these vaccines.

It all comes back to the 3 Q’s: Quality, Quantity, Quickly – get these right and you can achieve 100% in one of the most important parts of calf rearing. If you have any questions about how to make sure your calf rearing systems are on track for success, talk to your local Anexa vet.

Quality: Colostrum >22% BRIX


Quantity: Aim 10% body weight (30kg calf = 3L; 40kg calf = 4L); tube feed if struggling


Quickly: Within 12 hours or as soon as after birth



Want to know more about the 3 Q’s of Colostrum management?

Read these previous Anexa articles:

Colostrum management is the key to preventing disease and death in calves

Colostrum & calf immunity – why is it such a race against the clock?


Share This