Neonatal Isoerythrolysis (NI)?

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chandab

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Ok, so I borrowed this information from a donkey/mule forum; but it happens in horses, too. How common is NI in miniature horses? Anyone know? Does anyone check compatibility with their new foals? [i never have, and to my knowledge this hasn't been a problem for me. I've only lost two foals; one late term abortion and one pre-mature foal that didn't survive.]

Not something we've talked about, so thought I'd ask.

Neonatal Isoerythrolysis (NI) in Newborn Mules The reported incidence of NI in newborn mules is about 10%, which is higher than the incidence in horses. All donkeys possess the red blood cell antigen known as donkey factor, therefore every donkey/horse breeding has potential for NI. Mules suffering from NI frequently manifest thrombocytopenia (low platelet count) as well as anemia, presumably because of the presence of anti-platelet antibody as well as anti-red cell antibody. Alloimmune thrombocytopenia (platelet destruction due to anti-platelet antibody) may occur without NI as well. The article below helped me so much to understand better and I'm prepared to do this.After all of the colostrum has been fed, a high quality powdered mares milk will satisfy the foals hunger for the next 24-36 hours. The directions on the powdered milk usually instruct a much more highly concentrated mix than is necessary. The least amount of problems are encountered with a 50/50 mix of powdered milk and water. Even with this watered down mix the foal will usually experience at least some gas colic over the course of bottle feeding. If the foal begins to nurse smaller amounts and wants to lay on its back with its feet curled up it is uncomfortable. 1cc of Bantomine can be administered orally with a syringe to help alleviate stomach pain. It is also imperative that the foal passes its meconium or first manure. An enema may be warmed up and gently administered if you see the foal straining to defecate.

If you have continued to milk the mare vigorously each time you feed the foal, at 30-36 hours you can begin to prepare to return the foal to normal nursing. At this time the foal should be bottle fed under the mare in a nursing position. Stand on the opposite side of the mare as the foal and hold the bottle very near her udder. You may have to allow the foal to get a hold of the nipple and then slowly move the bottle into position. Completing 2-3 feedings in this position will hasten your success as the foal transitions completely back to the mare. The final bottle feeding you should milk the mare and use that to fill your bottle and feed the foal so it gets used to the new taste.

Finally, at 36-48 hours old, the foal can no longer absorb any harmful antibodies. Now it is time to get the foal nursing solely from the mare. Position yourself again on the opposite side of the mare from the foal and bait the foal with the bottle of mares milk. Hold the bottle as near to a teat as you possibly can. You can also coat the mares teats with milk. Attempt to get the foal to look for the bottle and move over to the mares teat instead. You can also dip your fingers in the milk and get the foal sucking on your fingers and moved over to a teat. Once they actually nurse from the mare nature takes over very quickly. Some mares are very tolerant of this process and some may need to be restrained. It is helpful to have a tube of Dormosedan Gel on hand. It can be administered orally and is a very effective sedative. It will not effect the foal.

Monitor the mare and foal carefully over the next hour or two to be sure the foal is nursing properly and the mare is stepping back into a motherly role. If the mare wasnt milked enough during the previous 48 hours she may have reduced milk production for a short time and you might have to supplement the foal with a bottle of powdered milk for another few hours until the mare begins to accommodate the entire meal.

Many farms have a veterinarian come out and do a foal wellness check. This is particularly important in an NI foal. IgG levels should be checked to be sure the foals passive transfer was successful. An apparently healthy foal can die in a matter of hours without the proper protection from infections. If the foal is checked at about 6 hours old, if it is found to have a failure of passive transfer plasma can be tubed orally and the foal can be rechecked. If you have a wellness check at 24-48 hours old and there is a failure of passive transfer then the foal must be sedated and plasma administered intravenously.

After 11-12 months of waiting, there is no reason to lose a foal to NI. It is your responsibility to test and also to know the symptoms and treatment. NI foals grow up to be healthy, normal mules with no adverse effects. As always, be sure to include your veterinarian in your plans and care.
 

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To my knowledge, I have never had a case here, although I do know of one "large horse" mare, who by the second foal from the same stallion lost a foal after delivery, but this first loss was thought to be from another cause. Then the 3rd breeding, during pregnancy (late term), the mare aborted the foal prematurely, and the vet told of her history suspected NI and found it to be the cause of the abortion.

The owner was told to never do that coupling again, and the mare went on to successfully be bred and deliver healthy foals to a different stallion.

For those who want to know more about NI and what it is, here's a good article by Dr Kathryn Graves, Maxwell H. Gluck Equine Research Centre, University of Kentucky, Lexington

Neonatal isoerythrolysis (NI) is caused by an incompatibility of blood types between a mare and her foal. If a foal inherits from its sire a red cell factor (antigen) that the mare lacks, the mare may develop antibodies to that antigen.
There is no harm to the foal in utero, as there is no comingling of the mare's blood with that of the fetus. However, these antibodies will be present in the mare's colostrum and will be ingested by the newborn foal. Following transfer across the foal's intestinal mucosa and entry into its bloodstream, the antibodies will attach to the foal's red blood cells and cause their destruction, resulting in a jaundiced foal and in severe cases, death, unless quickly diagnosed and treated.

How mares become sensitized to red cell antigens they don't possess is a mystery, but transplacental hemorrhage or exposure to the foal's red cells during parturition have been suggested as possible mechanisms. A mare's first foal is seldom affected, but subsequent foals carrying the offending antigen will be at risk.

Horses have complicated blood types, consisting of 30 or more factors (antigens) that are grouped into systems (A, C, D, K, P, Q, and U). Factors within each system are designated with small letters. The factors most commonly associated with NI are Aa and Qa. Mares that are negative for these factors are the ones most at risk for developing anti-red cell antibodies. Approximately 19% of Thoroughbred mares are negative for the Aa or Qa antigens, and 17% of Standardbred mares are negative for Aa (Qa being extremely rare in Standardbreds). The relative frequency of these antigens in a breed determines the risk of a mating producing an NI foal. For example, only 3% of Thoroughbred mares might be negative for Aa, but since most Thoroughbred stallions are positive for Aa, the risk is greater that an incompatibility will occur.

Managing mares that are at risk for producing an NI foal consists of screening these mares for anti-red cell antibodies within the last 30 days of pregnancy or after udder development has begun. Sera from mares are tested against a panel of known blood types to determine the specificity and concentration of any antibodies that are present. While it has been standard practice to withhold foals only from mares with a titer of 1:16 or greater, some practitioners believe that any positive result, regardless of strength or specificity, is sufficient cause to withhold the foal from nursing. This is because in some cases, a low pre-partum titer to a red cell antigen may increase significantly just prior to foaling.

If an anti-red cell antibody is found in the mare, the foal should not be allowed to nurse the dam and should be given banked colostrum; the dam's colostrum should be stripped out over a 24-hour period before allowing the foal to nurse.

In a mare with a history of producing an NI foal, either all subsequent foals should be withheld from nursing the mare for 24 hours, as explained above, or the mare should be bred only to stallions that do not possess the red cell antigen to which she is sensitized.

Since DNA typing has widely replaced blood typing for identification and parentage purposes in the last 15 years, the number of laboratories offering blood typing and antibody screening services has diminished. Some large veterinary clinics offer NI testing and red cell typing for the most common antigens involved in incompatibilities. The University of Kentucky Animal Genetic Testing and Research Laboratory is the last major facility offering full blood typing and screening services.
 
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chandab

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Did you do a lot of repeat breedings? Since that seems to be when it comes into play, if it will.

I only have one stallion, so all breedings this year are my first repeats, so this issue crossed my mind.
 

madmax

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My understanding is that one does NOT let the foal nurse the colostrum and one should strip the mare of it.

In the old days there was a quick test for this by mixing blood from the foal's navel at birth with the mare's colostrum and see if it clots. Does anyone else remember this?
 
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Debby - LB

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It is a concern in Miniature Horses, and more common that you'd think. Most don't call it by it's proper name, but simply refer to it as RH Factor incompatibility. It is fairly easy to test for.

....take a drop of blood from the foal (I would get it when the umbilical chord broke) and mix that with a drop of colostrum from the mare. If it mixes and stays mixed, everything is alright. If it separates and appears to curdle, which it will do very quickly, do NOT LET THE FOAL NURSE but get the vet there IMMEDIATELY to give the foal IgG, or an artificial colostrum or colostrum from another mare. Then keep the foal with the mare, but muzzled for 48 hours and bottle feed with another milk source. Milk the mare so that she won't stop making milk. After the colostrum is gone the foal can start nursing without danger. It is only the antibodies in the colostrum that fights the foals immune system.
 
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Chanda, it wasn't my large mare, but I knew of her. And yes, she went on to have several more healthy foals when bred to a different stallion. Having this factor doesn't negate future breeding for the mare -- it doesn't make her useless in a breeding program -- but you have to select a different stallion to breed her to.

I had a large number of foals born here, with many different mares having multiple births to the same stallion(s) and never experienced it.

According to a report from the College of Vet Medicine at the University of Florida, the disease has a prevalence of 1-2% in horses, but some breeds have a higher frequency. It was discovered in the Fresian breed in 2007, and many reports discuss the frequency in Thoroughbreds, Standardbreds, Arabians, Morgans, Quarter horses and Tennessee Walking Horses.

I know that you have that wonderful little donkey and you said that the occurrence in donkey's / mules is about 10%. I did find something interesting on breeding donkeys by Traub-Dargatz JL, McClure JJ, Koch C, Schlipf JW (1995) Neonatal isoerythrolysis in mule foals. J Am Vet Med Assoc 206:67-70

Donkey RBC antigen: In one experimental study, the risk of an incompatible mating between a horse and a donkey (or the chance of a mare becoming sensitized to this antigen) was 100%. This high rate of sensitization may be due to a naturally occurring antibody that horses possess to this factor, differences in placentation in mule pregnancies, or differences in the antigenicity of this factor. Because clinical NI in mule foals only occurs ~8-10% of the time, it is suggested that many mule foals may have subclinical NI because the concentration of colostral antibodies against the foal’s RBCs that is required to cause overt clinical signs may differ between horse and mule foals.

Chanda, are you expecting a baby from your little donkey? I thought only your mini girls were pregnant this year.

Debby has given an excellent was to test to be sure and it is simple to do if you're concerned Chanda and everyone who just wants to be sure.

Until we know if there's a way for this information to be on both forums, the only way I know to do it, is to "move" it to the main forum with the "arrow" that will allow the topic to show on both forums. I'm going to do that now, but hope all members here on our Mare/Foal forum will continue to post on the thread -- which can be done by simply clicking on the topic link on the Mare/Foal forum which will take you to the main forum automatically for posting.

Join in everyone!
 
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chandab

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I put it on mare stare forum, as it's very relevant to foaling, but I can see where more might be interested in the info.

There is a slight chance that my little stallion caught my donkey, but I'm doubtful.
 

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Absolutely, it's VERY relevant to the Mare/Foal forum, but is also a very good topic for those mini owners who may be considering making some mini mules or may have experienced an "unknown cause" for a loss. Of course, we welcome all those to join us on the Mare/Foal forum, but wanted to share this with those who post here on the Main Forum and also need this important information -- especially if there are some mini mules expected or planned or those looking for information on a possible reason for a loss.

Thanks Chanda for this great educational topic that all can benefit from!

~~Diane
 
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Debby - LB

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Definitely relevant for all breeders. Is is more common than you think.

Topics like this are also saved in our informational files under Breeding Horses 1 and 2. I probably should compile more of these important topics and add them to the info. pages then keep a link to those pages on the top of the forums. It's in the navigation, but a more visible link might help people find it.

It would be nice if we could keep everything front and center, but we can't. This will be in both forums because it's linked but eventually will drop off the boards only to be see by a Google search, that's why it's important to have the info. pages and the "best of" forums....such as this post from like 2006 http://www.miniaturehorsetalk.com/index.php?/topic/58375-rh-factor-and-foaling/
 
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Rocklone Miniature Horses

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I need to stop reading these things. Its a miracle anything gets born
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Rocklone Miniature Horses

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I convince myself more and more every day that something will go wrong! I'm hoping that it is a good experience cause if its not i don't think my breeding programme will take off :p
 

chandab

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I convince myself more and more every day that something will go wrong! I'm hoping that it is a good experience cause if its not i don't think my breeding programme will take off :p
Try to relax a little and remember to breathe.With breeding minis, we all have at least one problem with breeding, but most of the time it goes ok.

I have lost two foals, both were mares purchased pregnant; one was pre-mature and didn't survive long, the other was a late term abortion. All four mares I hand bred here, conceived and had live foals; I still have 3 of those four foals (one 7 years old now, the other two are coming 4), I did sell one foal. I pasture bred last year, we'll see soon enough how successful that is for me.
 

weerunner

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hmmm, I will definitely be testing Eclipse's foals blood when it is born. Could be a very good explanation why she aborted her last two foals.
 

Mona

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hmmm, I will definitely be testing Eclipse's foals blood when it is born. Could be a very good explanation why she aborted her last two foals.
No, Neonatal Isoerythrolysis cannot cause a miscarriage. It is not harmful to the foal until it starts to drink it's dam's milk.
 

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