Maximising Calf Immunity

It has the potential to prevent every infectious disease a heifer is likely to get in her first month of life. It is only administered twice, orally. It is readily available on every dairy farm, and best of all it is FREE!!


Colostrum is the magic bullet that every dairy farmer dreams about, but very few utilise to its full potential. EVERYONE who has improved their colostrum transfer has the same story, “less sick calves, less drugs used, more heifers reared to weaning, less work and LESS STRESS”


American and Australian research has clearly shown that up to 70% of calves left to suckle naturally from the cow will NOT receive enough colostrum. Not only is their natural protection from disease reduced, but their exposure to adult manure (the main source of scour infections) is significantly increased when left with mum.

“Anything which adversely affects weight gain in the first 56 days of a calf’s life will affect future milk yield.

This is a quote by Dr. Vic Cortese at the World Buiatrics Conference 2014 where he presented on calf rearing and the effect of illness on calves’ future performance.


The long reaching effect of calf illness highlights the importance of disease prevention, especially in the first 56 days of life. The biggest variable between how calves perform in terms of growth rates, morbidity and mortality is the dose of colostrum received by calves.


It is estimated from Australian data that 20-40% of calves fail to get sufficient antibodies in the first 24 hours of life to give them immunity against common bugs causing calf scours, pneumonia and other illness. There is also wide variation on farms with some farms recording >90% of calves having almost no immunity.

How do we maximise immunity?

Calves need a minimum of 150g (and ideally >200g) of antibodies in the first 6 hours of life. To achieve this you must know the concentration of antibodies in the colostrum. If colostrum only contains 25g/L of antibodies, the calf could not physically consume the required 6-8L (to ingest 150-200g antibodies) within 6 hours to achieve sufficient immunity.


The best and cheapest way of determining the concentration of antibodies in colostrum is using a Brix refractometer. Colostrum with a Brix value >22% will have >50g/L of antibodies. Therefore 3L of colostrum fed ideally by milk nipple, or oesophageal tube (if the calf won’t drink the entire amount within 10 minutes), within the first 6 hours of life will give the calf >150g of antibodies. Ideally, this is followed up with 2L of colostrum approximately 12 hours later.

Why can’t we just let calves suck colostrum from their dam?

If calves are left on their dam to suckle colostrum, less than 50% of them will acquire immunity.


Please call us if:

  • You are experiencing calf mortality above 2%
  • More than 10% of calves require treatment with electrolytes or any drugs
  • Calves are failing to double their birth weight by 8 weeks of age