Wednesday, March 17, 2010

3/17/2010: New Foals Arriving!

Vet Tip of the Day: Keeping your Newborn Foal Healthy
Key Words: neonate, umbilicus, colostrum, IgG, plasma, passive transfer
It is spring, and for me that means lots of work related to reproduction.  Ironically, it seems like I'm either stopping reproduction (gelding colts) or enhancing reproduction (breeding mares) every day.  But the most fun for me is welcoming new equine lives into the world.

I strongly recommend that you look at the Mare & Foal page on our website (link at top of blog page).  There is an excellent revue of prepartions needed before your foal is born.  What I'd like to do  here is speak in a bit more depth about the equine neonate and its particular susceptibility to infection in the first few hours & days after birth.

Foals are born with naive immune systems.  This means that when they hit the ground, they have NO circulating antibodies.  Their bodies begin responding to challenges and producing antibodies immediately, but the development of a fully competent immune system takes time, and in the first hours and days of life an invading organism can quickly gain the upper hand.  Antibodies are the body's infantry in the fight against infection.  Without antibodies, we succumb to disease causing organisms and we die.  End of story.  No exceptions.  Foals obtain critical antibodies in colostrum, the first milk produced by their dams.  The absorption of colostral antibodies by the foal from the mare's milk is called passive transfer.  Two basic things have to happen for successful passive transfer to occur. 
1) The mare must be healthy and produce sufficient quantitiy and quality of colostrum.  Older mares, malnourished mares, and maiden mares all are at risk of producing poor quality colostrum.  The ideal high quality colostrum producer is a mare between 6-10 years of age, giving birth to her second foal, on an excellent diet, vaccinated 4-6 weeks before foaling to increase antibody production against common diseases
2) The foal must drink and abosrb the colostrum.  The antibodies in colostrum are very large molecules.  The foal is born with specialized cells in its small intestine which can absorb these antibody molecules.  These cells only function for 12-24 hours after the foal is born.  Therefore, the foal MUST consume adequate colostrum during the first 12 - 18 hours of life.  After this small window of opportunity closes, it doesn't matter how much colostrum the foal drinks, it will not be absorbed.

Sounds simple, but often it is not.  Maiden mares may be nervous about allowing foals to drink and they may have limited quantities of colostrum.  Foals born in severe cold may be slow to rise and may have delayed intestinal motility decreasing colostral absorption.  Foals born prematurely or with musculoskeletal abnormalities may also be slow to rise and nurse. All foals should be up and nursing within 2 hours.  If a foal is not nursing vigorously within 2 hours please contact your veterinarian immediately.  Foals are very delicate creatures and succumb rapidly to infections in the first few days of life, often with fatal consequences.

Let's assume your foal gets up and nurses appropriately and your mare has adequate colostrum.  Great! However, there are still risk factors which may predispose your foal to early infection.  The envivonment in which the foal is delivered should be clean and dry.  The foals' umbilicus is a little highway into the foal's blood stream for disease causing bacteria in the foal's environment.  The umbilicus should be dipped in 2% idodine or dilute chlorhexidine 3-4x in the first 24 hours of life to help minimize the chances of ascending infection through the umbilicus.

Even with successful passive transfer (absorption of colostral antibodies) if a foal is exposed to a large number of pathogenic (disease causing) bacteria in the first hours of life, they are at risk of developing a bactrial infection of the blood stream.  This is called neonatal septicemia, and is often fatal in foals.  The key to succeful treatment of neonatal septicemia is early detection and aggressive intervention. 

I cannot emphasize enough the importance of contacting your veterinarian IMMEDIATELY if any of the following is true:

Your foal is 2 hours old and is not up and nursing
Your foal shows signs of decreasing energy/lethary/depression at any time in the first week of life.
Your foal develops diarrhea.
Your foal shows signs of abdominal pain - foals with colic often roll up on their backs and lie like a dog with all 4 legs in the air, or they may roll and thrash like an adult horse with colic.
You notice that the mare's bag is full or is dripping milk and the foal is not nursing vigorously at least twice every hour.
You notice that your foal is constantly trying to nurse and does not lie down and sleep between nursing - this is hallmark sign that the mare does not have sufficient milk productio and the foal is hungry.

Please remember that foals are particularly delicate creatures - early intervention can often save them, but a delay of a few hours can mean the difference between life and death for a sick neonatal foal.

All foals should be examined by a veterinarian at 18-24 hours of age at which time a physical  examination and blood test to check for adequate colostral absorption is performed.

Don't be complacent about your newborn.  If you have any questions or concerns, call your veterinarian immediately - these precious lives are in our safekeeping, take the best care of them you possibly can.  Please read the mare/foal care information on our website.

Enjoy,
Chrysann

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