Maintaining calf health is essential to achieving calf rearing targets and profitability on a dairy farm. Following feeding costs, heifer rearing is the second largest expense in the dairy system, accounting for 20% of the total costs.

Calving dairy replacement heifers at 24-months of age is necessary to obtain maximal lifetime productivity in the pasture-based system in Ireland.

Optimal nutrition, stress reduction and disease control in pre-weaning calves will help ensure maximal health and daily live weight gains, paving the way for calves to achieve long-term targets and profitability.

Calves are born with no immunity and rely on colostrum from the cow to provide immunoglobulins (antibodies) that will protect them and fight disease from the environment. This is known as passive immunity.

Passive immunity can protect the calf for roughly the first four weeks of life, then the antibodies from the colostrum wane below protective levels.

Calves are born with the building blocks of an immune system, but it takes time for a complex cascade of hormones, mediators, and immune cells put these blocks together and learn to respond to challenges in the environment. This is known as acquired immunity.

Acquired immunity begins to develop in the calf slowly at 2-4 weeks of age, but it will not reach protective levels until about eight weeks of age.

This then leaves calves with a critical immunity gap from about 4-8 weeks of age when their colostral, passive immunity has waned, but their developing active immunity has not reached adequate levels. Calves are especially vulnerable to pathogens and disease during this period of immunity gap (Fig. 1).

Stress will inevitably occur throughout a calf’s development and take a toll on calf health. Examples of stressful events are cold temperatures, regrouping, dehorning, and weaning (Fig. 2).

Fig 2: Stressful events: Temperature change; Weaning; Management challenges; Pen or grouping changes; Ventilation issues; Dehorning.

When a calf experiences a stressful event, the body will release cortisol. This cortisol release results in a natural decline in immunity, making the calf especially vulnerable to infections that can result in scour and respiratory disease.

Whether stress events are unplanned or part of necessary management, each event will result in a compromise of immunity and expose the calf to risks of disease and reduced daily live weight gains.

Omni ProCalf combines a quality calf milk replacer with OmniGen AF, a unique nutritional speciality product that helps calves maintain an optimally functioning immune system, especially under stress.

Omni ProCalf with OmniGen AF works by increasing levels of L-selectin, a molecule that helps the neutrophils receive the necessary signals and move quickly to the point of infection to fight pathogens. During stress, L-selectin levels decline, and this is one of the reasons immunity is naturally suppressed during any stressful event such as weaning.

By counteracting the negative impact of stress on immunity, Omni ProCalf supports the calf’s natural immune defences and makes calves less vulnerable to disease which can reduce health events and improve productivity.

In addition to combating the negative immunity impacts of stress, OmniGen AF can help minimise the immunity gap calves experience.

OmniGen AF fed to mature, dry dairy cows can increase the antibody content in colostrum, which can improve the passive immunity of the calf. Omni ProCalf fed to the newborn calf can help improve acquired immunity development. The combination of beneficial effects from OmniGen® AF fed to the dry dairy cow and Omni ProCalf fed to the neonatal calf can result in a reduced immunity gap, protecting calves from disease (Fig. 1).

Omni ProCalf improves calf health by:

Over 1,100 university, research, and field studies have been published demonstrating the benefits of OmniGen AF.

A study in New York evaluated growth rates in Holstein heifers fed OmniGen AF with milk replacer from birth to four months of age. OmniGen AF resulted in a daily live weight gain 12.5% higher than the group that was not fed the supplement, and these results can have a far-reaching impact on a dairy farm (Fig 4).

In a Cornell study, for every 1kg of pre-weaning average daily gain, heifers, on average, produced 850kg more milk during their first lactation.

A trial in Pennsylvania with 200 Holstein bull calves found calves fed OmniGen AF had fewer health issues than the group that was not fed the supplement. This resulted in a 43% reduction in medicine use (Fig. 5).

With new legislation prompting restrictions of antimicrobial use, Omni ProCalf can help farmers save money on treatments and reduce medicine use on the farm.

Omni ProCalf provides pre-weaned calves with a high-quality, whey-based milk replacer conveniently blended with OmniGen AF nutrition speciality product. Calves will receive optimal nutrition in addition to a scientifically researched product proven to help calves maintain a healthy immune system, optimise daily live weight gains, and reduce medicine use.

Pat O’Hanlon based in Markethill, Co. Armagh, milks a herd of Holstein Friesian cows. He calves all year round and rears all the calves on the farm. His heifer calves are calved down at two-years and his bull calves are finished off farm also.  

"It’s ever more important to rear healthy calves and make adjustments to what you do to reduce antibiotic usage on farm," said Pat.

Describing his experience using OmniProCalf, he said: ‘’I was very impressed with the palatability of OmniProCalf and the calf’s willingness to take to the milk. I also noticed less illness when they were on it and the calves appeared to be generally healthier.

"Also I was impressed with the support offered to me from the PharVet team and their on hand nutritionist Bill Ryan."

By Dr. Lauren Popiolek, Interchem and PharVet veterinary technical advisor

OmniProCalf is part of PharVet’s new Calf Rearing Gold Standard Programme. The gold standard is a systematic approach of best practice on the basic principles of calf rearing.

Also included within the programme is a feeding regime which contains nutraceutical, calf health products, rehydration, biosecurity, hygiene and temperature control.

For more information on OmniProCalf or PharVets new Gold Standard, contact your local representative via the details below: