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Optimising Calf Immunity

The health and welfare of your dairy calves is essential, not only to their immediate performance, but also to ensure they are able to generate a sustainable profit throughout their adult life.
Born with a naïve immune system, calves need to build their immunity from the colostrum they receive from their mother and from the environment they are brought up in until their own immune system is developed. Several factors can impact the health of the calf during this critical period, which unless managed correctly will impact the future potential of the animal, making them subsequently more susceptible to key bovine diseases.

04-03-2021, updated on 05-03-2021

Thankfully, there are many ways we as farmers, vets, nutritionists and animal health professionals can help to optimise the immune function of calves. The first step is always to ensure a calf receives the right amount of the best quality colostrum very soon after birth. This blog will summarise the options that can be taken beyond this point to ensure the continued development of a strong immune system.



Nutrition is the key to developing a strong immune system: the cells of the immune system require adequate and appropriate nutrition to function optimally. Making sure each calf drinks the allocated amount of milk or eats the required amount of creep feed is therefore very important. In terms of dietary value and quality, the feed presented to the young calf must contain the necessary balance of protein and nutrients, with any imbalances in the diet rectified by making small adjustments to the ration: for example, any feed wastage is a sign of a problem and should be investigated.



In order to reduce the risk of infection from environmental pathogens, high standards of hygiene must be maintained during the first weeks of a new calf’s life. Effective management protocols should be implemented to ensure anybody entering or leaving the calf shed disinfects their hands and footwear and that they are wearing clean clothing. Wearing disposable gloves will help to reduce the transfer of pathogens between batches of calves.

All feed stations should be cleaned daily and water troughs emptied and cleaned on a regular basis, with fresh bedding provided at least twice a week. A deep clean of the calf accommodation should also be carried out between batches of calves, with an approved disinfectant used to ensure key pathogens are destroyed.

Good ventilation is also imperative: a steady supply of fresh air not only keeps the calves at a comfortable temperature and humidity level, but also moves any unwanted airborne pathogens away from the calf. Air flow at calf level should ideally be around 0.2m/second (to avoid drafts whilst also providing sufficient flow to remove pathogens) with the use of smoke bombs providing a quick and easy way to assess air flow. Where air flow is too low (for example in sheds which weren’t purpose-built to house calves) it may be necessary to install a forced-ventilation system.



Vaccination is widely accepted as an effective tool in preventing disease and as an important step in maintaining high health. It is important to discuss and evaluate with your farm veterinarian which diseases are a risk to your herd. Your veterinarian can advise you an appropriate vaccination program if necessary. It is also important that animals are healthy in the first place and are not living in unsuitable conditions, as this will prevent the vaccine from working optimally.


Stress compromises immunity: the release of cortisol can affect white blood cells and render them unable to work efficiently. Remaining calm, handling calves gently and limiting the number of people in the calf shed will reduce stress in the calf population and will also minimise the potential for diseases to spread. Increasing calf comfort by regularly introducing clean bedding can also reduce stress by encouraging extended lying times which is very important for young calves.
Limiting the amount of changes to the calf’s routine is also key to reducing stress, so it is essential to plan early and to combine jobs where possible. Keeping group sizes small and avoid any unnecessary group changes will also help to limit stress and prevent cross-contamination of diseases from one group to the next.

Weaning is one of the most stressful periods in a calf’s life, so it is important to ensure that this process is carried out over an adequate amount of time and in a manner which limits the calf’s exposure to any excessive stress factors.

Monitoring and Recording

Measuring health parameters and growth rates enables you to assess how well your calves are performing and to evaluate any changes you make to the way they are managed. Reviewing your records will also enable you to identify any improvements in the way your calves are being managed and allow you to implement these benefits into future management protocols. to this end it is worth working with your vet and nutritionist to help keep your calves healthy as this in turn will help to reduce antibiotic usage and ensure optimum levels of calf growth and development are achieved.

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OmniGen AF for calves

OmniGen AF contains a unique and patented blend of ingredients which, when used on a daily basis, helps to minimise the effects of expected and unexpected stress events by supporting healthy immune function. Read here more about what you need to know about the immune system of a cow. Backed up by a wealth of scientific data as well as a series of recent on-farm evaluations, OmniGen AF has been shown to provide significant benefits in calf rearing:

  • Reduction in medicine spend:
    • A 2010 trial carried out in Pennsylvania, USA looked at the effects of feeding milk powder with OmniGen AF to 200 Holstein bull calves for 20 weeks.
    • The trial found that those calves fed with OmniGen AF had fewer health issues than those that did not receive it, leading to 43% less medicine costs (Bewley, 2010).
  • Increase in liveweight gain:
    • A study (Bewley, 2011) assessed growth rates of Holstein heifers on a commercial calf unit in eastern New York, USA. The trial showed that calves that received OmniGen AF from birth to four months of age had a daily liveweight gain 12.5% higher than a control group which did not receive it.

Additional information and advice

For more information about how OmniGen AF could improve the health and performance of your dairy calves, please click here.

Alternatively, if you’d like to find out about the current immunity status of your herd and to find out how we could help to optimise your herd’s performance please click here to request a call from one of our dairy technical specialists.

Navaratnam Partheeban
Navaratnam Partheeban
As a Dairy Veterinarian, Theeb is very passionate about the health and welfare of dairy cows and ways to improve productivity of the dairy farm. He finds it important to spend time with farmers and allied industries to help find solutions to on-farm and agricultural sector problems.

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