Feeding whole milk to dairy calves

With some milk companies reducing the amount of milk collected due to the COVID-19 outbreak, dairy farmers are looking at alternative ways to use excess milk.

One method to use surplus saleable milk is to feed it to calves instead of a milk replacer. Saleable whole milk is consumable milk, and is not waste milk that might contain antibiotics or have a high Somatic Cell Count (SCC).

We always advise that you seek advice from both your vet and nutritionist before changing your feeding system.

Back to Coronavirus: support for dairy farmers

Top tips for feeding surplus whole milk to dairy calves during Coronavirus

1. Feed milk from healthy and disease free cows

Risk assess your herd and consider the calf health implications from feeding contaminated milk; the financial benefit from feeding spare saleable milk might not be worth the risk. We recommend you discuss the disease profile of your farm with your vet to make an informed decision if feeding excess milk is a suitable option on your farm.

There is the potential to spread diseases that you have on your farm to the calves by feeding fresh milk. Whilst the biggest risks for feeding whole milk to calves are Johne's, Salmonella dublin and Mycoplasma bovis, many other diseases may also be spread via milk. In any case extreme caution should be taken when feeding whole milk to calves as you may not be aware of all the diseases present on your farm. This also applies to bull calves as there can be potential onward spread of infection with some diseases such as Mycoplasma bovis.

Feeding pooled milk to calves is a recognised risk for Johne's disease infection, if one or more of the cows are excreting the organism in faeces or directly into the milk, contamination is a risk. This risk can be reduced by:

  • Only feed milk from repeated and recently Johne's negative tested animals, do not feed milk from animals with any indications of Johne's disease
  • Avoid feeding pooled milk; if this is not possible limit the number of cows contributing to milk pools

Infected cows can excrete tuberculosis (TB) bacteria in milk. Calves fed milk from infected cows can develop bovine TB, and there have been severe outbreaks in milk-fed calves. It is not recommended to feed milk from TB reactors or inconclusive reactors to calves or other livestock. Never feed milk from another herd as TB-infected cows may be present, even if the herd is officially TB free.

Due to the large number of calf health issues with Mycoplasma bovis, the risks of feeding potentially contaminated milk far outweigh any savings to be made.

2. Do not feed waste milk

Waste milk from cows being treated with antibiotics should not be fed to calves, because of the risk of antibiotic resistant bacteria developing. Milk from cows with mastitis often contains large numbers of bacteria and feeding this milk can potentially spread infection from your herd to the calves. Mycoplasma bovis often manifests as mastitis or high SCC in cow and is another reason not to feed waste milk to calves.

3. Gradually transition from milk replacer to whole milk to reduce stress

Consider continuing to feed your very young calves (up to 3-4 weeks of age) milk replacer, to ensure they have the best possible start. For older calves, gradually transition from milk replacer to whole milk to reduce chances of digestive upset. Milk replacer should be mixed according to the manufacturer's instructions, prior to mixing with whole milk. Blend milk replacer with whole milk for 2-3 days before fully switching to whole milk as shown in the table below.


Milk replacer

Whole milk













4. High standards of hygiene is essential

When feeding calves whole milk, hygiene is essential as the bacteria present in whole milk can double every 20 minutes. 

  • Always ensure you use clean, sterilised equipment for collection (see protocol below)
  • Transport milk in clean containers with lids
  • Bulk tank milk may be more hygienic although it may not be desirable to feed pooled milk
  • If milking into separate containers from a dump line, be aware of faecal contamination in the parlour. Closed containers will help avoid contamination
  • It is key to feed whole milk quickly so that there is little time for bacteria to multiply before the milk is fed
  • Clean and disinfect all kit after each feeding. Think about the set up for cleaning equipment, if it is an easy job it is more likely to be done properly

Follow the six step feeding equipment washing protocol:

Further information can be found in the Calf management resource.

5. Do not store milk for longer than 24 hours

The initial amount and type of bacteria in milk will have an effect on how long milk can be stored before bacteria reach levels that can affect calf health. Low temperatures slow bacterial growth in whole milk. Store milk in the fridge at a temperature of 4oC for up to 24 hours.

You may consider preserving whole milk by acidifying or fermenting with yogurt. We would advise that you seek advice and guidance from your vet or nutritionist if you are considering these options.

6. Pasteurise milk where possible

On-farm pasteurisation can be used to reduce bacterial load and to reduce the risk of disease transmission. Pasteurisation is an effective means of reducing the microbial load of milk and improving overall milk quality. Although pasteurisation reduces the microbial load, it is not sterilisation and a heavy bacterial load in milk will not be completely eliminated by the process. In addition it does not remove potential antibiotic contamination.

  • If possible pasteurise all whole milk fed to calves. It is important to remember that pasteurisation will not completely remove the risk of diseases such as Johne's
  • It is important to use pasteurisers according to manufacturer's guidelines to preserve the important proteins in milk that are necessary for the calf

Delaying weaning

If you are considering delaying weaning on your farm, speak to your vet and nutritionists to decide the best approach for your calves. Monitor growth rates to ensure calves are at their target weight for their age. Gradually wean the calves by reducing milk over 7-14 days. You can reduce milk by either reducing the volume of milk fed per feed or the number of feeds per day. This will lead to increased starter intake and avoid a growth check after weaning and minimise weaning distress. Avoid stressful procedures at weaning such as vaccination, disbudding and castration.

Find more information in our Calf management guide

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Expert advice gratefully received from Aurelie Moralis (Zoetis), Colin Mason (SRUC),  Ginny Sherwin (University of Nottingham), Jamie Robertson (Livestock Management Systems Ltd), Jessica Cooke (Volac) , Jud Heinrichs (Penn State University), Mark Little (Trouw Nutrition), Peter van’t Veld (Denkavit), Robert Hyde (University of Nottingham), Sam Strain (Animal Health and Welfare NI), Steven Morrison (AFBINI).