QUESTION: We had two mares deliver huge red water bags that were almost too tough to puncture with a knife. They both had long and hard labors, not normal for either mare.
One mare's foal was huge but never got up. We bottle fed it and tried for 2 days to get him up but he died.
The other mare had a tiny foal that appeared normal in every way. It went outside and froliced like a normal colt. They were born an hour apart and they both died on the same day. One was expected, the other was a shock.
The healthy foal appeared to have just dropped in the stall. He had not thrashed as if he had colicked or suffered.
I am wondering what that huge alien looking bag was and why they had it. Shouldn't the water bag break before it comes out? Was this the water bag?
ANSWER: Your mares apparently had "red bag deliveries." The huge, alien-looking bag almost certainly was the placenta.
In a normal foaling, the foal's hooves rupture the placenta at the inner opening to the cervix when the foal begins its passage through the birth canal. The placenta should not appear until after the foal is born. It normally remains attached to the wall of the uterus until the foal is free of the birth canal. Yes, the "water bag" should break, but not exit the mare before or with the foal.
Not to confuse you, but there are two membranes
surrounding the foal, both of which contain fluid:
1. the amnion or
amniotic membrane, a thin, semi-transparent sac immediately surrounding the
foal, contains amniotic fluid.
2. the placenta (or chorioallantois) is a
thicker membrane that is attached to the lining of the uterus. It nourishes the
foal through exchange with the mare's circulation. The fluid between the
placenta and the amnion is called allantoic fluid. The side of the placenta
facing the uterus is reddish and velvety (this is the membrane that bulges out
of the vulva in a red bag delivery).
There is a thin area called the cervical star in the placenta. When labor begins, this is where the foal's hooves rupture it, releasing the allantoic fluid in a trickle or a gush that we often call the "water breaking."
Sometimes, the amnion is also ruptured, releasing the amniotic fluid as well. Often, the amnion remains intact. That is the smooth, whitish bubble you sometimes see at the vulva before you see the foal's feet. This membrane is very fragile and usually tears without help as birth proceeds. If it does not break, it is very important to break it and move it away from the foal's nostrils to prevent suffocation.
A red bag delivery occurs when the placenta separates prematurely from the uterus and exits the birth canal with the foal. The placenta is difficult for the foal to rupture except at the thin cervical star area mentioned earlier. In a typical red bag delivery, it is the bulge of the intact placenta and the fluid it contains that you see first. That's the alien-looking bag you described. It is crucial for the foal's survival that someone cut the placenta open. Unfortunately, in this case it didn't affect the ultimate outcome.
If your mares were on fescue (grass or hay), this could have contributed to the problem. Some fescue grasses carry a fungus that produces toxins (poisons) called ergot alkaloids. Some signs of fescue toxicity in pregnant mares include overdue foals (prolonged gestation length); tough, thickened placentas; difficult foalings; birth of dead or weak foals that may be large, normal in size, or small for their age; higher than normal foal mortality rate; and inadequate milk supply (sometimes no colostrum/milk production at all).
Fescue isn't the only culprit. Other pasture grasses can be infested by other fungi that produce ergot alkaloids, also. There is a study underway in Canada, investigating this very topic. Ergot alkaloids can survive the hay curing process, therefore infested grasses can result in infested hays.
Although there is often no explanation for why a mare would have a red bag delivery, the above is one possible answer.
This information is based on information provided by Dr. Chris King-
Christine King BVSc*, MACVSc (equine medicine), MVetClinStud Cary, North
Carolina
(* Australian equivalent of DVM)
EDITOR'S NOTE: This syndrome is one of the ways that "Foal Loss Syndrome" presents.
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