Practical ideas and answers to calf health and calf scours prevention.

By Rebekah Mathews, M.S.

IgY products come from eggs – and use immunoglobulin Y in an attempt to mitigate pathogens that challenge a calf. But hyperimmunized egg fails in single-dose products — the physiology of it is quite simple.

IgY is made from a chicken, not the maternal cow

Every colostrum talk discusses the “gut closing” that begins at birth. The gut needs to allow colostrum the chance to send the critical immunoglobulins (IgGs) across and into the calf to provide immunity. Those immunoglobulins were created to work within the system they are in — the calf is built to absorb what the colostrum provides. The gaps present in the first day of life close rapidly, after which the calf can no longer absorb these immunoglobulins. But absorbed IgGs circulate for weeks to provide a calf with lasting immunity.

No IgY or IgG can be absorbed after Day 1

The absorption of IgY on the first day of life is poorly understood, and studies that exist find the absorption into circulation is low. IgY is larger than IgG — so that means the potential window of absorption is even shorter. If a dose is given after the gut has closed beyond the point of no return, the IgY can only bind pathogens in the gut — it cannot be absorbed. IgY fails to protect that calf over time, when so many scour pathogens occur.

IgY has no lasting effects in the calf
after it has left the digestive system

Let’s double down. A one-time paste/gel/feeding of IgY can bind pathogens ONLY IN the gut before being absorbed. IgY can ONLY do this if it is constantly present in the digesta – the food mass within the gut. Once it passes through the calf, no possible benefit is left. When immunoglobulin are not present, they cannot bind pathogens.

Want to pile on? No IgY product has USDA claims on reducing scours or death in calves. USDA claims require third-party verification that a product is effective, safe, and consistently meets potency specs. Claims by unlicensed products promising to decrease scours and mortality are serious and harmful; both to an animal and to profitability.

There are no USDA claims on any IgY products

One more reason to avoid. Some IgY products also contain live CFUs. Probiotics should NEVER be fed before, with, or within many hours of colostrum feeding – ideally not until the gut is closed. Probiotics and immunoglobulin can get preoccupied with each other in the gut lumen, bind each other, and not be absorbed. This is a great way to miss out on the benefits of colostrum, while paying to do it.

Don’t put your eggs in the wrong basket. Put them in a carton in your fridge. First Defense’s product line (Tri-Shield® and Dual-Force®) offers the only gel tubes and boluses with a USDA claim to reduce scours and death loss – and it is the only hyperimmunized colostrum available. This is what the calf is built to absorb – protection and immunoglobulins from colostrum. Immediate and lasting.

Field Product Comparisons

*You might hear people say, “It’s the same as Tri-Shield but cheaper.” The comparison is flattering, but it is also misleading. IgY paste/gel products simply do not provide lasting immune support to calves.