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What is a Red Bag Delivery?

By Dr. Heather Pedersen BVSc, Kamloops Large Animal Clinic

Let’s start at the beginning…


ithin the uterus the foal is surrounded by a thin white sac (the amnion), and then a thicker red membrane (the chorioallantios). This red membrane is smooth on the inside (toward the foal) and has a velvety texture on the outer surface where it is firmly attached to the uterus. At the cervix, the red membrane does not have this velvety appearance, instead it has a smoother appearance, this area is called the cervical star.

oxygen from the placenta. The red bag must be opened so the foal can be delivered. Open the red bag immediately - with scissors or by tearing it. Once the membrane has been cut, deliver the foal as soon as possible. Once the foal has been delivered it should receive oxygen if available. Because the foal will have been deprived of oxygen for a period of time it may develop problems due to this period of decreased oxygen. A red bag delivery increases the chances that the foal will develop neonatal maladjustment syndrome (dummy foal syndrome). Have the foal examined by a veterinarian within the first few hours of birth. (Editor’s note: I was most curious about this and asked Dr. Pedersen more questions… How often does this happen to mares? Is it more apt to happen with a maiden mare or broodmares? What might cause the red membrane to separate prematurely? Her response…

Normal presentation

The velvety surface of the red membrane is actually millions of Velcro-like attachments, this close attachment allows transfer of oxygen and nutrients across the placenta and to the foal. In the uterus the foal relies on this attachment for oxygen, once the foal is born it will rely on environmental air. In a normal foaling when the cervix relaxes and the uterus starts to contract, the pressure at the cervix breaks the red membrane at the cervical star. This is when the ‘water breaks’. This happens inside the mare so you will see the fluid but you don’t see the red membrane at all until after the foal is born and she passes the placenta (afterbirth). After the ‘water breaks’ the thin white sac (amnion) will protrude through the vulva within 5-10 minutes with the foal’s nose and two front feet inside it. The foal is then delivered within 15-30 minutes.

“Red bag is more likely if the placenta is thickened from infection or inflammation, a condition called “placentitis.” Mares exposed to fescue grass in late pregnancy can also have a thickened placenta. However often there is no obvious cause. Although no exact statistics are available, thankfully it is very rare. It is not any more likely in maiden vs second or third foals.”)

Abnormal ‘red bag’ presentation

In a red bag delivery the red membrane (chorioallantois) separates prematurely and it does not break open at the cervical star. It is then pushed out through the vulva intact and presents as a ‘red bag’ at the vulva. This is a true emergency. Because the placenta has separated, the foal is not receiving HCBC 2010 Business of tHe Year • 23

Saddle Up May 2015  
Saddle Up May 2015  

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