Feeding whole milk to dairy calves

During periods of low milk price, dairy farmers are looking for other ways to use excess milk.

One method is to feed surplus saleable milk to calves instead of milk replacer.

Saleable whole milk is consumable milk. It’s not waste milk that might contain antibiotics or have a high somatic cell count (SCC).

Always speak to your vet and nutritionist before changing your feeding system.

Only feed milk from healthy, disease-free cows.

Carry out a risk assessment for your herd and consider the calf health implications. The financial benefit of using surplus milk might not be worth the risk.

Discuss the disease profile of your farm with your vet before deciding if this is a suitable option.

Feeding fresh milk can spread diseases that you already have on your farm to the calves.

The main risks include:

• Johne's disease
• Salmonella Dublin
• Mycoplasma bovis

Take extreme care 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 infections such as Mycoplasma bovis can spread further through the herd.

Do not feed waste milk from cows being treated with antibiotics. This increases the risk of antibiotic-resistant bacteria developing.

Milk from cows with mastitis often contains large numbers of bacteria and can spread infection from your herd to the calves.

Mycoplasma bovis often manifests as mastitis or high SCC, which is another reason to avoid feeding waste milk.

Consider continuing to feed your very young calves (up to 3–4 weeks of age) milk replacer to give them the best possible start.

For older calves, introduce whole milk gradually to reduce chances of digestive upset.

Mix milk replacer according to the manufacturer's instructions before combining with whole milk.

Blend milk replacer with whole milk for two to three days before fully switching to whole milk, as shown in Table 1.

Table 1. Milk replacer to whole milk transition guide

Bacteria in whole milk can double every 20 minutes at room temperature after pasteurisation, so hygiene is essential:

• Always 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
• 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 – make the cleaning process as easy as possible

• Rinse at 32 to 38°C
• Soak at 54 to 57°C with chlorinated alkaline detergent solution
• Scrub
• Wash at above 49°C
• Rinse with acid sanitiser
• Dry

Do not store milk for longer than 24 hours.

The initial amount and type of bacteria will affect 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 4^oC for up to 24 hours.

You may consider preserving whole milk by;

• Acidifying
• Fermenting with yogurt
• Adding potassium sorbate

Seek advice and guidance from your vet or nutritionist if you’re considering these options.

On-farm pasteurisation can reduce bacterial load and reduce the risk of disease transmission.

However, it doesn’t sterilise milk or remove antibiotic contamination.

• If possible, pasteurise all whole milk fed to calves
• Always follow the manufacturer's guidelines to preserve the important proteins in milk that are necessary for the calf
• Pasteurisation reduces bacteria counts initially, but remaining bacteria begin to double every 20 minutes at room temperature. Hygienic handling, storing and feeding of milk after pasteurisation is important

• Colostrum: 60 minutes at 60 ^oC to protect antibodies
• Whole milk:
  • 60 minutes at 60 ^oC
  • Above 70 ^oC for 15 to 25 seconds (may reduce bacteria linked to Johne’s, but this doesn’t eliminate all of it. Always use milk from Johne’s-negative cows)

If you’re considering delaying weaning on your farm, speak to your vet and nutritionist.

• Monitor growth rates to ensure calves are at their target weight for their age
• Gradually reduce milk over 7 to 14 days
• Reduce either the volume of milk fed per feed or the number of feeds per day
• Encourage starter intake to avoid a growth check after weaning and minimise weaning distress

Avoid stressful procedures at weaning, such as:

• Vaccination
• Disbudding
• Castration

Acknowledgements

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) and Steven Morrison (AFBINI).