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  • Writer's pictureSarah L Rhoades, DVM

What's the deal about colostrum?

Okay! I know it's cold, I know it's nasty out - so why am I harping about spring grass associated laminitis, foaling preparedness, etc.?

Because now is the time to prepare - preventative medicine is anticipating health concerns that commonly happen and taking reasonable measures and actions, to monitor for and circumvent these disease process from even becoming a problem to begin with!

And with foals, preparedness, prevention, is so vital - because a lot of the time, I can't fix a sick foal, at that point the die is cast and it's simply too late... and it's heartbreaking.

So, what the deal with colostrum in foals? What is it exactly?

Simply put, the colostrum is the mother's first milk the foal consumes. Weeks before parturition (the actual birthing process) the mare's body begins concentrating her immune system's antibodies in her developing milk. This process is the reason you really want to try and booster your mare's vaccines approximately one month before she's due - that's sufficient time for her immune system to respond to the vaccines and for those antibodies she develops to consolidate in her colostrum - so by doing so you're essentially vaccinating both the mare and the foal.

But why is that so important to the foal?

In human being a vast majority of maternal antibodies are transferred transplacentally - for some antibody types, the levels may even be higher in the child than the mother before birth! While some transfer of antibodies are transferred via the mother's colostrum, it very minimal comparatively speaking. (If you're interested in the nitty gritty, scientific, details 'The Impact of IgG transplacental transfer on early life immunity' by GG Fouda, Immunohorizons. 2018 Jan 1; 2(1): 14-25. is a fascinating read... boy was that a mouthful!)

This is simply not the case in foals and calves.

In horses (and cattle), over 90% of all antibody transfer takes place in the first 24 hours after birth when the foal consumes it's mother's colostrum.

What this means is, your foal is immunologically, almost completely unprotected at birth.

Actually, lets delve into these time frames a bit - most of that antibody absorption occurs in the first 6-12 hours of life, it tapers after that - the rate of transfer is greatly reduced the following 12 hours. And after 24 hours (or less), no more transfer take place. When a foal fails to absorb antibodies from his mother's colostrum we call that Failure of Passive Transfer (or FPT) - these foals have no effective immune system, and it takes 4-6 months for a foal to start developing his own immune system and make his own antibodies.

And, I mean, consider, your foal will probably literally eat his Mom's poop (behavior called copraphagia - which is actually completely normal behavior)... this no immune system thing is a big deal!

It's a big deal for your foal to have impaired access to his mother's colostrum, and it's a big deal if it happens in the first few hours of life.

And believe me when I say, there are lots of things that can go wrong to cause this: many a foal has slipped under the fence and been physically separated from his dam, fescue toxicosis of the dam has caused many a 'dummy foal' that had difficulty getting up and swallowing for the first few days of life, or for that matter it has also caused many a mare to not produce milk (and therefore colostrum) at all at the time of birth.

I could go on and on, but the point is it's necessary to be vigilant and watchful with these guys - many of these problems could be avoided by simply observing the birth (I have a friend that watches her thoroughbreds born a state away on her phone - cameras are cheap now!), removing the mare from pasture in her last trimester of pregnancy, and doing a simple diagnostic test to check and make sure your foal absorbed those antibodies.

IV serum administration for a healthy foal that suffers from failure of passive transfer is not cheap, and I would prefer you avoid it with preventative measures... but it's a lot cheaper and a *lot* more successful than trying to treat a sick foal with no immune system. To impress the significance of that: I consider that last category a hospital situation - there's really not a lot I can do to help you on the farm that going to make any difference at all when that situation happens - throwing antibiotics and serum at a foal like that is like trying to build a dam by throwing pebbles in the ocean, you're in trouble and you need excavating equipment and boulders.

What I'm trying to hound home is taking precautions to avoid this situation is going to save you a lot of money, and more importantly, a lot of heartbreak.

I usually recommend a post foaling check somewhere around 12-24 hours after birth. 1) To make sure mom is healthy, as this is a dangerous time for her - retained placentas can lead to deadly complications including endotoxemia, sepsis, and laminitis, etc. 2) To make sure the foal is healthy without serious or dangerous, congenital defects as well as to check his blood for IgG levels. If his level are low, there are some things I can do to help decrease our odds of facing some severe, potentially deadly complications.

Did you enjoy this post? Want to learn more? Here's another great articles from The Healthy Newborn Foal: Why is Passive Transfer Important? – The Horse

Sarah L Rhoades, DVM


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