By Philip J Morrison BVSc, Cambridge
Calves are born with no antibodies and only start producing their own from 4 to 6 weeks of age. The only way that calves can get antibodies before this is through good quality colostrum. Calves need to take in approximately 10 – 15% of their body weight of “Gold Colostrum” in the first 24 hours to ensure sufficient levels of antibodies are absorbed. This ideally should be given as 2 litres at 6 hours and a further 2 litres at 12 hours of age. If calves won’t suckle then top up with a stomach tube.
Calves can only absorb antibodies for up to 24 hours after birth so it is vitally important to ensure all calves receive adequate quantities of “Gold Colostrum”.
Gold colostrum is defined as the first milking of colostrum from a healthy cow, with a Brix reading over 22%. Healthy cows produce antibodies to viral and bacterial diseases such as BVD, IBR, Rotavirus, Coronavirus, Leptospirosis, Salmonella, E.Coli, Clostridia, and many more environmental bacteria. These antibodies are concentrated in the colostrum at the first milking after birth. Vaccinating cows with Rotovec or Scourguard will provide additional antibodies to help protect calves from common neonatal diseases.
First colostrum can be tested using a Brix Refractometer. Readings above 22% are “Gold Colostrum” and should be used for feeding to newborn calves. Any colostrum below 22%, even if it is first colostrum, should be pooled and stored for feeding to older calves.
The concentration of antibodies in the colostrum is reduced to half by the second milking.
Continue to feed fresh or stored colostrum for the first 4 days as it gives local immunity in the gut and is a very good source of nutrition, having almost twice the amount of solids, 4 times more protein and 60 times more antibodies than milk.
Failure of Passive Transfer
If calves don’t receive sufficient colostrum in the first day of life, and hence their blood antibody (Immunoglobulins/IgG) levels are low, they are said to have Failure of Passive Transfer of Immunity (FPT).
This can be caused by:
Colostrum with poor levels of antibodies – a cow leaking milk, been milked out already, poor quality colostrum.
Delayed ingestion of colostrum e.g. not receiving colostrum for 18 to 24 hours, being born weak/cold, poor mothering, recumbent cow or poor udder conformation.
Calves left on cows for more than 12 hours have a high rate of FPT and are at a high risk of neonatal disease, ill-thrift and mortality.
In recent studies around 50% of dairy calves had FPT when left on their mothers for 24 hours, compared to less than 6% of calves having FPT in a trial where they were collected from the paddock twice a day and given 4 litres of Gold Colostrum in the first 24 hours.
I can hear you saying “that’s a lot of extra work” but to ensure you rear calves that have the ability to fight neonatal disease and ill-thrift and become your future herd, this is the best policy. The cost of extra labour at this early stage far outweighs the cost and time of rearing and treating unhealthy calves.
From a health and welfare perspective, we must ensure that ALL calves-irrespective of their destination – receive Gold Standard care.
Getting it right
To ensure calves are getting adequate colostrum, they can be blood tested at 2 to 7 days of age to check antibody levels. This can be done 2 or 3 times through the season to ensure colostrum management and calf feeding systems are continuing to work as the season progresses.