Is failure of passive transfer affecting your stock?
June 2023

Is failure of passive transfer affecting your stock?

Unlike humans, the bovine placenta prevents the transfer of large antibodies essential for immunity, from crossing the placental-blood barrier and into the calf. Instead, newborn calves must ingest colostrum to absorb antibodies in their first 24 hours to obtain immunity until their own immune system becomes functional. This is referred to as ‘passive transfer’. When calves do not absorb enough antibodies they are said to have “Failure of passive transfer” or “FPT”.

In a 2015 NZ study of 4000 dairy calves from 106 seasonal pasture-based farms across nine different regions, 33% of calves had FPT, but the prevalence ranged between 5% and 80% on individual farms.. This study indicated many calves are not getting enough good quality colostrum immediately after birth to ensure passive immunity.

What are the effects of FPT?

FPT increases the risk of death, disease and ill-thrift in dairy calves, and has been associated with long-term reductions in productivity. Calves with FPT are more susceptible to diarrhoea, respiratory disease and other illnesses. FPT can also lead to reduced growth and subsequent milk production.

So what can you do to help?

STEP 1 - Test your calves for FPT

A simple test to check for FPT is by blood sampling twelve healthy calves (not scouring or dehydrated), between 24 hours and seven days of age, for laboratory analysis of total protein.

STEP 2 - Test colostrum for quality. You can use a BRIX refractometer to test your colostrum quality. BRIX readings of 22% or more indicate high quality colostrum with lots of antibodies. We have refractometers in stock in the clinic.

STEP 3 - Follow some basic quality controls for colostrum

  • Feed new-born calves 10 to 15 percent of their bodyweight (4 to 6L for a 40kg calf) of first milking only or “gold” colostrum within the first 6 to 12 hours of life. It’s most effective to give smaller feeds more frequently (i.e. two feeds within the first 12 hours of life).
  • Test the quality of colostrum from individual cows and try to feed colostrum from cows that have BRIX readings of 22% or more (Or the highest you can find).
  • Clean is key – do not leave colostrum to sit without a preservative or refrigeration and always make sure it has a lid. If you wouldn’t drink it, don’t feed it to the calves. Bacteria destroy antibodies and inhibit their absorption.
Refractometer for testing colostrum quality

If you would like to discuss this further, chat to your vet. We’re here to help.