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The benefits of feeding strategically immunized egg antibodies to dairy calves

Jackson Matschke for Progressive Dairy Published on 31 July 2020

Calf diarrhea is the leading cause of death among dairy calves and likely contributes at least in part to the second leading cause, pneumonia, due to calves being in a weakened state.

There are many tools we can use to help promote calf health, such as excellent colostrum protocols, sufficient nutrition and clean, dry, ventilated housing. But what if our best management techniques aren’t quite overcoming the challenges our calves are facing? What additional tools are available that don’t require administering antibiotics to our calves after the fact? Using egg antibodies to help prevent scour-causing pathogens from overwhelming the calf’s defenses and causing an infection may be one technique to consider.

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Average daily gains (ADG) are useful but not the only indicator of calf quality. The link between ADG and first-lactation milk production is well established. Researchers found a statistically significant link between calves that suffered from diarrhea and had received antibiotic treatments and milk production. Calves that experienced diarrhea alone did not suffer from reduced milk production during the first lactation; however, calves that received antibiotic treatments as well did.

How do egg antibodies work?

Egg antibodies are ingested orally (for calves with milk or milk replacer) and provide localized immunity in the gut against the pathogens for which there are antibodies in the eggs. IgYs work in a similar fashion to IgGs (colostral antibodies) in the gut but have a much greater ability per gram to bind to antigens than IgGs do. This means that a relatively low feeding rate (grams per day) has an effective level of antibodies (depending on the product). It should be noted that IgYs do not cross into the bloodstream and have no effect on passive transfer. Therefore, they are not a substitute for an excellent colostrum protocol. The IgYs bind to, and reduce, the pathogens’ ability to attach to the gut lining and are passed in the manure.

There are a variety of feeding protocols but, in a preventative application, the goal is to reduce the pathogen load on the animal at its weakest point (zero to 3 weeks old). During this timeframe, the calf is depleting its colostral antibodies (passive immunity), but its active immune system has not yet had sufficient time to be educated to the disease challenges in its environment (Figure 1).

calf immunity within the first 14 days

They may also be fed as a supportive once the animal has developed a clinical case of a particular challenge – and works in much the same way. The antibodies bind to the antigens and reduce the pathogen load in the gut. The downside of this approach is: The animal has already developed significant enough symptoms that intervention is necessary. The ideal application is prophylactically, so the animal either does not display any symptoms or has minor symptoms and needs minimal intervention (i.e., electrolytes) to make a full and speedy recovery.

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The science of strategically immunized egg products

Strategically immunized egg products have been used for longer than might be initially apparent. Originating with Roman soldiers raiding local hen houses in newly conquered lands, they realized this helped prevent gastrointestinal issues in the men and horses.

More recently, many dairy farmers would add raw eggs from their hens to calves’ milk. These hens were well adapted to the immunological challenges of the farm and produced a customized IgY profile for that specific farm.

There are numerous studies showing the usefulness of IgY products in a variety of animal models, including calves, piglets, chickens and humans. The common theme among these studies is a reduction in the length and severity of gastrointestinal infections when used in either a prophylactic or reactive method for a wide variety of pathogens.

Egg antibody products are produced by vaccinating laying hens against specific pathogens of concern. The egg yolk is the chicken’s only tool for passing along antibodies to its offspring (much like bovines and colostrum). When it is exposed to a disease challenge, either from a vaccine or the environment, it creates antibodies against that challenge and concentrates them in the egg.

Observed scour days when fed egg antibodies vs. control 

In the creation of immunized egg products, these eggs are collected and processed into a powder that can be fed to calves. Some products include the white of the egg as well, which has a variety of antimicrobial and anti-inflammatory compounds that may also benefit the calf during a gastrointestinal disease challenge.

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Research supporting immunized eggs

The main goal of strategically immunized egg antibodies is to reduce the length and severity of gastrointestinal illness to reduce mortality and, particularly, morbidity. Calves that have had more severe illness and received increased antibiotic treatments can show lifelong effects.

Research trials performed by Grober Nutrition and Trouw Nutrition show overall reduced treatments and improved recovery time when compared with calves in control groups (which received whey powder as a placebo). Calves in all trials were multisourced, transported by truck and of unknown passive transfer and nutritional status upon arrival.

The on-farm trials showed numerical but not statistically significant differences in bodyweight gains. As the use of immunized egg products does not change the nutritional status of the animal, large differences would be unlikely. Effective preventative treatments like strategically immunized egg antibodies are useful on-farm tools for farmers and veterinarians to consider adopting when appropriate. The benefits stretch beyond the immediate health of the calf to a greater potential as heifers become part of the milking herd.

Additionally, preventative treatments have the benefit of reducing labour and management challenges.

As stewards of our industry and the greater health of our planet, adopting best practices to preserve our current tools is an admirable goal and also the right thing to do. Putting this attitude at the forefront of calf health will allow our farmers to remain viable in an ever-changing landscape of caring for young animals.  end mark

Jackson Matschke
  • Jackson Matschke

  • Young Animal Specialist
  • Grober Nutrition
  • Email Jackson Matschke

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