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OmniGen-AF FAQ

What is OmniGen-AF?

OmniGen-AF is a unique, patented nutritional specialty product from Phibro Animal Health Corporation that is recommended to be fed to dry, pre-fresh and lactating cows every day to help support normal immune function in the face of expected and unexpected stress events.


Why should I feed OmniGen-AF?

Studies have shown continual use of OmniGen-AF helps support a healthy immune system, which may help result in fewer health events, a lower somatic cell count and fewer cases of mastitis and metritis.  This, in turn, may lead to higher milk production and fewer unplanned culls.


What events or factors can contribute to elevated stress in dairy cattle?


  • Calving
  • High Milk Production
  • Forage and feed quality challenges
  • Pen changes
  • Stocking density
  • Weather
  • Dry off

These examples are some of the most common sources of stress in dairy cattle.  Well defined management practices including nutrition programs, herd health programs and milking procedures are a must in terms of minimizing the negative impact of known stress events. Short term or unexpected challenges have impact as well.  These may include sudden changes in temperature and humidity, housing, overcrowding, or a disruption in forage quality.


How does stress impact immune function?

  • Research has  demonstrated that cortisol, the ‘stress hormone’, is closely associated with reduced immune cell function
  • In stress conditions, neutrophils (a type of immune cell) are compromised and have a reduced ability to detect and move into tissues being invaded by pathogens
  • This occurs because the neutrophils  fail to express adequate levels of an immune biomarker called L-selectin
  • L-selectin allows neutrophils to move along blood vessels and into specific tissues being invaded by unwelcomed organisms.
  • Neutrophils with normal levels of L-selectin expression move efficiently into affected tissues working to kill bacteria and eliminate infection


What information is available on the role of OmniGen-AF in supporting normal immune function in dairy cattle?

Since 2002, numerous field studies and published research projects (conducted privately and with key University partners) have consistently demonstrated that OmniGen-AF helps support a healthy immune system.  Our research has shown significant improvements in innate immune function, herd health metrics, and productivity. Our Dairy Technology Specialists can assist in providing you with materials to review from our extensive portfolio of resources.

Our most popular field study is the OmniGen Difference Challenge summary spanning 6 years and over 400 herds in North America.  A short review and video are available at:


What is the recommended feeding protocol for OmniGen-AF?

OmniGen-AF is recommended to be fed to dry and lactating cows at the rate of 56 grams per head per day.  It takes 45 to 60 days after the first feeding for OmniGen-AF to become fully effective in its role in supporting normal immune function.  It takes 5 to 7 days to lose the effect.


What other products are available like OmniGen-AF?

Other specialized products positioned as being “like” OmniGen-AF should be subject to careful review.  Remember, OmniGen is a patented technology.  It is important to ask for a review of specific research and field studies that demonstrate efficacy.  Are the studies directed specifically at supporting normal immune function?  Do the studies specifically state objectives focused on measuring parameters of normal immune function?  When reviewing self-published studies, are there corresponding University studies available?


Research conducted with OmniGen-AF has demonstrated specific differences with the innate immune system that include greater sensitivity in responding to stress, and more rapid restoration of normal immune function after a stress event has ended.  Studies conducted by teams at the University of Georgia, Virginia Tech University, the University of Arizona and the United States Department of Agriculture Animal Research Service have all made significant contributions to the scientific understanding of OmniGen-AF and its role in helping to support a healthy immune system.


Where can I learn more about immune function and stress in dairy cattle?

Visit the resources section on our website at Articles that go into greater detail include;

Relationship Between Stress and Health in Cattle (Parts 1 & 2)

Jeffery A. Carroll, PhD and Nicole C. Burdick Sanchez, Ph.D., Livestock Issues Research Unit, USDA-ARS

The Immune System of Ruminants

James D. Chapman, Ph.D., Director of Research and Technical Services, Phibro  Animal Health



You can learn more about OmniGen-AF by contacting us at 1-800-677-4623, through our website, or through your area Dairy Technical Specialist.

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